Renji Abarai

is the Lieutenant of the 6th Division in the Gotei 13 under captain Byakuya Kuchiki. Renji Abarai starts out as an antagonist, but after his surprising defeat by Ichigo Kurosaki, saw the error of his ways and joined the fight to save his childhood friend Rukia Kuchiki. Renji ranked consistently high in the first few character polls, but has now fallen from the Top 10 most popular characters(weeded out by newer characters like Grimmjow and Ulquiorra.)

Appearance
Renji is one of the more unusual characters in Bleach in terms of his appearance, with a long crimson hair, which is usually kept in a high ponytail, and his entire upper body being covered in tribal tattoo work. How he got these tattoos is unknown, but it appears that with every achievement Renji attains, his tattoos increase as well, starting from his early days as a Shinigami candidate until when he was imprisoned by Byakuya Kuchiki (his tattoos cover his entire back at this point of time). He dresses in the standard Shinigami outfit, though he usually includes some sort of elaborate headgear (usually expensive-looking glasses or a white headband). All of Renji's sunglasses are from Seireitei's popular "Silver Dragonfly Glasses Store" and cost half a year's worth of his paycheck. Unfortunately, every time he wears a pair, they are broken in one way or another (usually in a fight with Ichigo). On these occasions, he replaces them with a tied towel, until he can purchase a new pair of goggles. His dream is to once wear a pair that he has designed himself.

Renji likes futsal, and he in his free time he works on assembling a team from the 6th Division, with more or less success. The current members are himself, Rikichi and the 4th, 8th, 13th and 20th seated officers; The 20th Seat acts as the Keeper.

Personality
As far as his personality goes, Renji is about as eccentric as any other Shinigami. He varies from smug and cocky in his first appearances to downright angsty and depressed after his major defeats, but shows himself to be an incredibly serious and determined fighter when confronted with an actual challenge. Renji harbours deep affections for Rukia Kuchiki, bordering on romantic love -- he is deeply grieved when she is adopted by Byakuya Kuchiki and later becomes obsessed with saving her, and he reacts with puppyish joy when she shows up during the Bount arc. This is proved numerous times throughout the story, particularly during his flashback of his youth with Rukia in Rukongai. Willing to fight, kill, and die for whatever he believes in, Renji is a dangerous man to those who stand in his way. He is much like Ichigo Kurosaki in many respects, and the two are mistaken for brothers in the anime's Bount arc. Ichigo claims they are cousins to keep things simple, allowing many hilarious situations to occur later. He likes taiyaki (a popular fish-shaped pancake usually filled with sweet bean paste) and dislikes spicy food.

History
Renji Abarai came from the 78th district of Rukongai and grew up as an orphan with several other children, including Rukia Kuchiki. The company of children lived by stealing or hunting for food. Though Renji and Rukia quickly discovered they had spiritual powers, they remained with their friends until they all died, which prompted them to become Shinigami for a better life.

At the Shinigami academy, Renji was admitted into the top class, being very adept at swordsmanship, although quite inept at Kidō. His senpai was Shūhei Hisagi. At the academy, Renji befriended Izuru Kira and Momo Hinamori, who each proceeded to become lieutenants. His relationship with Rukia became distant after her adoption by the Kuchiki family since he felt he had no place interfering with her life now that she was a noble, despite the fact they both seemed to regret losing the company and confidence of the other. Abarai decided it was best to let her enjoy life as a noble, telling himself not to interfere no matter what happens.

Renji, Kira and Hinamori served under Sōsuke Aizen and Gin Ichimaru in the 5th division, after which Kira and Hinamori were put under Ichimaru and Aizen in the 3rd and 5th divisions respectively. The rebellious Renji was moved to the 11th Division and eventually rose to the 6th seat. During his time in the 11th Division, he befriended Ikkaku Madarame, who taught Renji how to fight. It was also shown that Renji was aware that Ikkaku had a Bankai, but refused to use it to train Renji. On the same day Rukia headed for the human world, Renji was promoted to lieutenant of the 6th Division. Izuru, Momo and Ikkaku knew about his past with Rukia, and told him that if they were such great friends he must go to her immediately before her departure. However, instead of going to see Rukia off, he decided to wait and surprise her three months later when the promotion ceremony was complete( along with her assignment.) Unfortunately by this time he was sent to bring her back to Soul Society. After meeting Byakuya Kuchiki, the 6th Division's captain, Renji's greatest dream has been to surpass him in strength.

Agent of the Shinigami arc
Renji first appears with Byakuya when they come to the human world to arrest Rukia. Their attempt is interrupted by Uryū Ishida, and Renji easily defeats him. Ichigo then arrives to stop them, faring better than Uryū after unlocking his hidden spiritual power. Byakuya steps in to save Renji, cutting Ichigo's sword down to just a stump and severely wounding him. He's later seen checking on Rukia at her cell, trying to cheer her up by saying that Byakuya won't let her be executed. Rukia, however, knows better, since Byakuya follows the rules above all else.

Soul Society arc
After Ichigo's group invades Soul Society to rescue Rukia, Renji blames Ichigo for Rukia's troubles and goes out to fight him alone. Though Renji does well at first, as he is not operating under a power limit as he was in the human world, almost knocking out Ichigo in his first attack. Even after Ichigo figures out the amount of consecutive attacks Zabimaru can use(3 times,) and attacks him while vulnerable Renji easily outmaneuvers him. The reason he was able to still dodge despite Kurosaki's perfect timing was simply their difference in level and speed. About to be dealt a finishing blow Ichigo dodges just in time, and begins to collect his reiatsu into Zangetsu. Completely shocked at such refined Spiritual Pressure in comparison to their first battle, Renji is finally hit by a direct unnamed Getsuga Tenshō which simultaneously defeats him and breaks Zabimaru. Before losing consciousness, Renji manages to walk towards Ichigo and explains the reason why he himself would not save Rukia, lamenting "the stray dog" in him. Upon seeing Ichigo's strength, he shamelessly begs Ichigo to save Rukia.

After being healed and imprisoned, as Byakuya claims that he has no excuse for losing if he was so eager to fight alone, Renji has a conversation with his Zanpakutō's spirit, Zabimaru. While Zabimaru wants a rematch with Zangetsu, Renji insists that they are no longer enemies. He then breaks out of confinement and finds his way to Ichigo, who is in an underground training area with Yoruichi Shihōin attempting to learn the Bankai of his Zanpakutō. Renji is fairly close to learning it, as well, and walks off to a separate part of the training area to finish, alongside a materialized Zabimaru.

While Ichigo continues training, Renji attempts to save Rukia on his own, only to be intercepted by Byakuya. Renji attempts to use his Bankai to defeat Byakuya, but both his inexperience and their difference in power leads to his defeat. Byakuya states that the main reason Renji cannot surpass him is because of their difference in class. Byakuya gives him the analogy of the monkey that is always trying to catch the moon, but no matter how hard the monkey tries, it is impossible. Renji attempts once last charge against Byakuya, but only succeeds in breaking his own Zanpakutō against Byakuya's immense spiritual power. Byakuya leaves a dying Renji with his shawl and acknowledges that Renji's "fang" finally reached him that time.

After being healed again, Renji attempts another rescue, this time finding Ichigo at the execution grounds with Rukia in tow. From the high perch of the execution stand, Ichigo tosses Rukia to Renji and orders him to defend her with his life. Renji willingly obliges and escapes from the execution grounds with Rukia in his arms. He barely makes it down the winding steps of the mountain they're on before being stopped by Kaname Tōsen, who teleports the three of them back to where they started. Sōsuke Aizen, having also teleported there, insists that Renji leave Rukia. Unwilling, he attacks Aizen along with Ichigo Kurosaki, who has not recovered entirely from his encounter with Byakuya. Despite their combined efforts, both are defeated easily. After Aizen's escape, Renji waits in the hospital with Byakuya, who was injured while saving Rukia from Aizen. When Byakuya asks why he's there, Renji responds that it's because he is his captain and that if Byakuya weren't alive, Renji would have no one to challenge in strength. Their conversation is interrupted by Ichigo, who's looking all over Soul Society for Rukia. He is then seen at the gathering where Ichigo and his group returns to the human world.

Bount arc
In the anime, after the events at Soul Society, Renji is assigned to the human world in Rukia's place. While he does not mention exactly why, he is angered at Ichigo's suggestion that he has been demoted from lieutenant. He also claims that Ichigo's inability to hide his huge spiritual power attracts Hollows, so he's there to lend a hand. During his visit to the living world, Renji stays at the Urahara Shop where they give him the nickname of nihongo (freeloader) and constantly deny him second helpings of food by playing on his guilt. When Ichigo starts to feel down about his early defeat by the Bount. However Renji, along with Ganju Shiba, provoke/attack him into realizing his strength again.

After the Bount fully reveal themselves, he joins Ichigo's friends in confronting the Bount at Kariya's mansion where Jin Kariya sacrifice Yoshino Sōma in order to create the bitto. While patrolling around the city, Renji finds a child being attacked by the bitto and defends him. The bitto eventually withdraw on orders, but Renji is already seriously injured and the child is almost completely drained of his soul. Renji is healed by Hanatarō Yamada, but the child is left struggling to stay alive. Later on during a short at the end of episode 92, it is revealed that Hanatarō successfully healed the child.

Meanwhile, Izuru Kira, Shūhei Hisagi, Rangiku Matsumoto, and Yumichika Ayasegawa are assigned by Tōshirō Hitsugaya to defeat the Bounts in the human world. The Shinigami find the hideout of the Bount and enter, but are all disabled by Ugaki's doll, Gesell. Renji, Ichigo, and his friends enter the cave later on and are also attacked by Gesell. Most of the group is left to tend to their injuries while Renji and Ichigo continue on, finding the other injured Shinigami along the way. After Gesell almost kills Yumichika Ayasegawa, Renji remembers the fighting spirit he was taught in the 11th Division and fights Gesell one-on-one with his Bankai. Yumichika keeps Ichigo from interfering, explaining that anyone who's been in the 11th Division believes their fights should be one-on-one and helping would be considered dishonorable. Renji manages to wound Gesell, driving it insane and causing it to kill its owner.

During the brief discussion period between Ichigo and the Shinigami after the Bounts enter Soul Society, an injured Renji (needing Yumichika's help to walk) tells the group he will also be returning to Soul Society. Although he does not enter Soul Society with Ichigo, he is later visited by Tōshirō Hitsugaya who wants to know if Renji knows anything helpful about the Bounts.

In Soul Society, Renji, Hitsugaya, and Matsumoto investigate reports of strange activity in a forest in Rukongai. By the time the three of them arrive in the forest, the Bount are gone. Maki Ichinose, on the other hand, is waiting for them, hoping to slow their pursuit and buy time for the Bount. Though initially successful, he is engaged by Kenpachi Zaraki and abandons his plan for the opportunity to kill Kenpachi.

After returning to Seireitei, Renji mainly fends off the many Shinigami possessed by the Bount Mabashi's doll, Ritz. After Mabashi is killed, he assists in caring for the wounded. He also helps take Rukia to the execution grounds later on, where Kariya and Ichigo are fighting.

Arrancar arc
With the emerging threat of the Arrancar in the human world, Renji, along with Rukia and four other Shinigami, are assigned to aid Ichigo Kurosaki in the living world. He appears to stay with Kisuke Urahara for the duration of his assignment.

When the Espada Grimmjow Jeagerjaques leads an assault on anyone in the material world, Renji battles the Arrancar Yylfordt Granz. Even with his Bankai, he is initially no match for Yylfordt. Things get even worse when Ururu Tsumugiya, the girl who works at the Urahara shop, interferes, injuring Yylfordt and forcing him to release his Zanpakutō, thus transforming into a bull-like creature. In this form, he impales Ururu on one of his horns and breaks through Renji's zanpakutō effortlessly. The tables are turned, however, when Renji is allowed to lift the power limit placed on him, allowing him to defeat Lfordt with some effort. Renji remarks that that if he had been fighting at full power the whole time, Yylfordt would have been more careful, and might have won.

After the battle, Urahara allows him to live at the shop. However, Urahara has persisted in avoiding Renji's questions (which are the primary reasons as to why Renji decided to go to Urahara's shop). During his time there, he helps train Yasutora Sado to increase his ability because of an agreement Renji made with Urahara; Renji will do whatever miscellaneous jobs Urahara asks of him for the next three months in exchange for the answers to all of Renji's questions.

Hueco Mundo arc
When the Arrancar launch a second attack with the purpose of distracting the Shinigami while Orihime Inoue is coerced into working for Aizen, Renji and Chad are left behind at the shop while Urahara goes to aid their allies. When Hitsugaya's team learns that Orihime is with the Arrancar, Renji volunteers for Ichigo's sake to form a team and "force" Orihime back to her senses and bring her back by coercion. He is denied that request and is instead forced to return to Soul Society with the rest of the Shinigami under the threat of Byakuya Kuchiki and Kenpachi Zaraki. Later on, however, Byakuya gives both him and Rukia permission to enter Hueco Mundo and fight alongside Ichigo's group.

After reaching Aizen's palace and discovering five separate paths, the group prepares to split up. Before they split up, Renji talks to Ichigo about the need to respect his comrades' skills in battle and leads the team in a chant used by the Gotei 13 in the past, vowing to never falter and come out alive together. Afterward, Renji is mistakenly chased by the Hollow Dondochakka Bilstin, even though they are allies. His appearance and attitude is enough to freak Renji out and convince him to run with the Hollow chasing after him. Both continue for some time after realizing this, arguing that the other should stop first. Eventually, Abarai senses Rukia releasing her Zanpakutō and stops, only to fall into a trap (along with Dondochakka) set by Szayel Aporro Granz, who mocks them and introduces himself. He reveals that the room they're in is designed to suppress Renji's Bankai, which was accomplished by analyzing the corpse of his defeated brother, Yylfordt.

Renji learns of Rukia's spirit pressure disappearing through Szayel. When Szayel mentions that the Shinigami was called "Kuchiki", Renji, using his Shikai, immediately attacks Szayel. Despite Szayel saying that Renji would not be able to injure him with just his Shikai, Renji manages to do so. Regardless, Renji cannot manage to duplicate the feat, and is saved by Uryū, who quickly ends up in the same situation. The two join forces to deal with Szayel's minions. In order to give Uryū an opening, Renji uses Zabimaru to tie himself and Szayel together, and then uses a Kidō spell which injures them both. Szayel retreats, falling into Uryū's trap, a massive gintō-triggered explosion. Szayel survives the explosion, albeit with near fatal injuries, and heals himself completely by eating Lumina. He then departs to replace his ruined outfit and formulate a new plan.

Renji and Uryu try to find a way out of Las Noches because their main target was to retrieve Orihime, not fight an Espada. They should also head out to help Rukia and Chad. However, Szayel manipulates the corridors to make them travel back into the same room. Szayel appears behind them, and releases his Zanpakutō. As soon as the liquid from Szayel's release makes contact with Renji and Uryū, multiple clones of them appear. Szayel then informs them that the device used to restrict their spirit energy has been deactivated, and that they can now fight against their clones at full power. After some time Renji activates his Bankai, causing all of his clones to activate their own. In doing so they destroy the room they are in and a now irritated Szayel disperses all of the clones of Renji and Uryu, saying that he will show them the "true power" of his Fornicarás. Szayel proceeds to use his Voodoo Doll technique on Ishida, which creates an Uryū doll out of him. Szayel hits the doll and reveals that he has control of all of Uryū's five senses. Despite Renji begging him to stop, Szayel rips the doll apart, and although Uryū didn't lose his legs, Szayel crushes the mini stomach organ inside the doll, critically injuring the Quincy. When Renji attacks, Szayel's Zanpakutō swallows Abarai, and creates a miniature Renji doll. Szayel rips the Renji doll in half and crushes his achilles tendon, making him unable to walk. Though it seems they will be saved by Dondochakka and Pesche Guatiche's new technique, Szayel has analyzed even their strength as well, and easily deflects it.

Szayel's further attempts are interrupted however, by Mayuri Kurotsuchi who fights and subsequently defeats the 8th Espada. Kurotsuchi offers heal the two of their wounds, and chooses to heal Ishida first. Renji is concerned that the Espada will kill his friends, and pleads to Mayuri to heal him first since he needs to rejoin the fight; Mayuri reassures Renji that the only one of his comrades still fighting was Zaraki, who had arrived to help Ichigo. Mayuri warns him that Kenpachi and his opponent will tear him apart if he interferes, before he looks inside of Szayel's lab. He is healed of his wounds afterward, apparently before Ishida as the latter was late to the battle.

Fake Karakura arc
Once Aizen, Gin, Tousen and the top 3 Espada have left, Orihime is left alone in Las Noches with Ulquiorra. Renji has been completely healed by Mayuri, so he heads to Las Noches in order to aid Orihime's rescue. He appears with Chad and Rukia to battle the Exequias, complaining that "There is no end to them"(the hollows.) The Exequias leader/creator is taken on by Rukia.

Powers & Abilities
Master Swordsmanship Specialist: Renji is highly skilled in swordsmanship techniques, having trained under Ikkaku Madarame. He has increased his strength and skill to allow him to become a captain-level fighter, so as to achieve his dream. What makes Renji so effective is the unique method in which his zanpakutō works, in the fact that his zanpakutō is more of an amalgam of a whip and a sword. Renji is versatile because of this, and to effectively wield it is a testament to his skill. When he releases his Bankai, as his zanpakutō becomes quite large in comparison to its shikai form, and is more complex in nature. It is worthy to note that he is also the only shinigami, lieutenant or otherwise, to injure an Espada using only his shikai. This was a feat even Tōshirō Hitsugaya, a captain, could not perform.

Flash Steps Expert: Knowing that Zabimaru's shikai attacks leave him open for counterattacks, Renji has become highly proficient at Flash Steps to compensate for it. Renji can even keep up with captain-level Shinigami for an indeterminate amount of time. He knows enough to be informed on their higher level techniques, though whether or not he can effectively use them is debatable.

Enhanced Strength: Like most upper-tier Shinigami, Renji has great strength. During the fight with Szayel Aporro's unique Fracción, Renji protected Ishida from a direct punch by one of the stronger(and larger) arrancar using both hands, and proceeded to throw him aside. Later, by spinning Zabimaru above his head, Renji was able to cause enough force to generate a whirlwind, blowing away all of Szayel's Fracción several yards despite their massive size. Szayel commented that he was using "brute force."

Kidō Practitioner: He can also use kidō like most Shinigami. While in the academy his skill for it was rather poor, as he stated they would constantly blow up in his face, he has become proficient enough to perform a Level 33 Kidō without incantation, not to mention with explosive power. His Kidō spell was powerful enough to injure an Espada, albeit hurting himself in the process. If Renji were to become more adept through practice, his Kidō would probably be less self-destructive.

Enhanced Endurance: Renji has been shown to have an incredibly high endurance, at least on par with Ichigo Kurosaki. In their first real fight, Ichigo defeated Renji by using a full power (although he did not say its name) Getsuga Tensho directly in shikai, and was still able to walk over, pick up Ichigo by the collar and remain conscious until his request was made. Later during his fight with Byakuya, he is hit directly by every blade from Senbonzakura Kageyoshi, and when he continues to fight he is pierced by five more blades. Even after such terrible damage he makes a last ditch effort attack, almost piercing Byakuya with Zabimaru, and finally falls defeated. Just one day later he is able to function enough to use shunpo, carry Rukia Kuchiki while running down Sōkyoku Hill, and even dual Aizen using his Shikai.

Determination: Renji has a ridiculously high determination, which also has a direct correlation with his endurance. Aside from the events during the Soul Society arc (see Endurance), Renji shows his will to fight when after finding out Rukia had been supposedly killed, he is finally able to injure the 8th Espada using sheer reiatsu through his blade.

High Spiritual Energy: Being a lieutenant of the Gotei 13, Renji already had a high spiritual energy. Upon learning Bankai, this power increased on a scale from 5-10. Rukia even comments after feeling his defeat that it was so high, she could not recognize it until it decreased which caused it to become more familiar to her. Szayel Aporro Granz was greatly excited to meet a shinigami who could use bankai, as one would need a high amount of power to achieve it, making him a rare specimen. Using his reiatsu in shikai, he was able to injure that same Espada by transferring it through Zabimaru.

Zanpakutō

 * Renji's zanpakutō is one of the rare whose spirit is actually seen, the other being Ichigo's and Hitsugaya's. Zabimaru is a nue (Japanese chimera in the form of a baboon with a snake's head for a tail), hence his name. Renji is very fond of his Zanpakuto, to the point where he easily gets agitated upon learning that it's gone or stolen without his knowledge. Zabimaru's spirit is portrayed as battle-loving and proud, similar in personality to Renji. It insisted on fighting Zangetsu again after losing, confident that it could succeed on the second attempt. Both the snake and baboon are capable of speaking (albeit usually in a finishing-each-other's-sentences manner), though the baboon is usually the more dominant one. The snake seems to be the more violent of the pair. Zabimaru's sealed form resembles a typical katana which, even in its sealed form is very useful in combat due to Renji's proficiency with a sword.Zabimaru has tattoos similar to Renjis' tattoos.

In an omake, Renji has shown some interest in having Mayuri give Zabimaru a sex change. How Zabimaru feels about this is unknown.




 * Shikai: Zabimaru's Shikai command is . In its Shikai, Zabimaru transforms into an even longer segmented blade; each segment is wider than the one preceding it from the hilt with 2 pick-like protrusions on the front and back of each segment, with the ones on the front much longer than the ones at the back. The segments are connected by a stretchable thread, making Zabimaru more useful as a whip than an actual sword, though it can serve as a regular sword just as easily, thanks to Renji's swordsmanship. Zabimaru's guard and handle pretty much remain the same in its Shikai release. While Zabimaru can be stretched to incredible lengths in its whip form, Renji has a limit of three consecutive attacks before having to bring the segments of Zabimaru back together for recovery - which makes him fairly vulnerable during the time interval. To make up for this, Renji usually relies on Shunpo for evasion as he retrieves Zabimaru's segments. Renji's Shikai, while durable to an extent, can ultimately sustain serious damage the longer the fight drags on. Not that it can't withstand dangerously prolonged combat, but even it has limits in enduring high-level attacks that were conducted by either the enemy or by Renji himself. Because of these many drawbacks, Renji states that out of all the other Zanpakutō wielded by the other Lieutenant Shinigami, Zabimaru is the most difficult to master.


 * Shikai Special Ability: Renji can also use his spiritual power to separate the segments and surround an opponent with them, allowing him to execute a one-shot omni-directional attack, but it is damaging to Zabimaru and leaves Renji defenseless. During the Bleach OVA, The Sealed Sword Frenzy, Renji attacked Baishin using the technique, and was seen afterward with a complete (unbroken) Zabimaru; However, this was not technically canon.




 * Bankai: : transforms Zabimaru into a massive version of its Shikai form resembling a skeletal snake. Zabimaru gains many more segments, which are much larger than in its Shikai form, and also gains a snake-like head about the size of a small car. Renji is also slightly transformed, gaining a fur cowl around his neck. The cowl appears to be the fur of an ape and thus, the ape's skull could be seen over Renji's left shoulder while the rest of the fur extends to cover his right arm. Unlike its Shikai, Zabimaru's segments are held together by Renji's spiritual power, allowing him to separate and reattach them at will. The segments themselves are extremely tough, making it extremely difficult to destroy Hihiō Zabimaru. Even if a segment is damaged, knocked off, or even destroyed, Renji can simply detach it and reform (or reconstitute) Zabimaru. Zabimaru itself, in Bankai form, does not literally "cut;" Renji usually catches his opponent with the snake-head of his weapon and smashes his opponent into the ground with it. The head has also proven capable of inflicting heavy damage through biting.


 * Bankai Special Ability: Zabimaru also gains a special technique known as after Renji becomes more adept with using his Bankai. The technique fires a dense blast of spiritual energy from Zabimaru's mouth. Unfortunately, the technique costs a substantial amount of energy from Renji which usually causes an aftermath that breaks the segments out of formation. He can also use a much more powerful Higa Zekkō, where all the segments detach, glow and sharpen using spiritual energy.

Relationships
Renji has encountered many characters in the series, and being a lieutenant in the Gotei 13, this is not surprising. The most prominent of these relationships are listed below:

Rukia Kuchiki
Rukia has been a friend of Renji ever since they were both kids growing up in the Rukongai. Both he and Rukia have shown that they care a lot for each other, evident that Rukia didn't know what to do with Byakuya Kuchiki proposed to adopt her, not wanting her friendship with Renji to end. Renji encourages Rukia to accept the proposal, thinking that she would have a better life if she did. After being defeated by Ichigo in battle, Renji pleaded Ichigo to save Rukia's life. When confronted with Byakuya, he fought to the full extent his body and soul could reach to save her. Rukia was distraught when she sensed his reiatsu disappear, realizing it was his when it decreased. He stated to Aizen he would never hand Rukia over to her, even if cost him his life. Renji and Rukia sometimes argue and fight with each other, very similar to how Rukia fights with Ichigo from time to time. During the Bount Arc, as soon as Renji found out that Rukia was in town, he reacted with puppy-like affection, bursting into the Kurosaki household shortly after calling her. In the Hueco Mundo Arc they both scorned Ichigo for not including them in the rescue attempt of Orihime, as they planned to go back to him from the start, attacking him as a tag-team before they gave him an explanation. Their feelings for one another have not been portrayed as romantic, at least not outright.

Ichigo Kurosaki
When Renji first encounters Ichigo, he sees him as an enemy and blames him for the loss of Rukia's powers. He also taunts Ichigo for not knowing the name of his zanpakutō. Later, when Rukia is sentenced to death, his hatred towards Ichigo intensifies and he heads out (without orders) to intercept and kill him. However, once Ichigo beats him, Renji's view on the situation changes and he asks Ichigo to save Rukia's life. After Ichigo and Renji become allies, Renji has shown that he trusts Ichigo completely and regards him as a friend. However, both of them fight and argue in many comical situations and seem to act similarly towards each other, making several of Ichigo's classmates (as well as his teacher) think that Renji is Ichigo's brother. Ishida comments that "he is just like Kurosaki," due to their seemingly reckless nature. They often compete whenever together, and regard each other as equals in combat.

Ikkaku Madarame
Due to his tendency to get into fights, Aizen placed Renji into the 11th Division, where he began to train under Ikkaku's tutelage. Renji started off poorly, being easily overpowered by Ikkaku. Eventually Renji learns his shikai, and is promoted to 6th Seat, though the order of which is unknown, all thanks to Ikkaku. During a training session, he is visibly saddened when Ikkaku tells him that his training would be over afterward. Ikkaku told him that he already knew everything he could teach, but Renji knew that he had a Bankai, and asked why he keeps it hidden. Ikkaku told him it was just "his style," and tells Renji that he does not want anyone but him and Yumichika to know about it, revealing trust between the two shinigami. Later on after Aizen's departure, Renji immediately asks Ikkaku to become the next captain sice he is the only seated officer capable of using Bankai, but Ikkaku explains his goals to Renji which causes him to never ask again. Ikkaku was also present during Renji's promotion to 6th Division Lieutenant, and revealed his knowledge of Renji's old friendship with Rukia Kuchiki, suggesting to go see her off. Renji and Ikkaku have a similar battle-loving natures, and trust each other without a moment's hesitation.

Sōsuke Aizen
The 5th Division Captain was interested in Renji's talent from the beginning of his shinigami career. Renji, along with Izuru Kira and Momo Hinamori were all manipulated by Aizen in some way. However, Aizen specifically stated that Abarai was the most dangerous or loose cannon so to speak. This is why he was sent to the 11th division as he was highly prone to fighting. The captain Aizen Renji knew was nothing more than an elaborate lie, so he fought with all his might to stop him from taking Rukia.

Yasutora Sado
During the Arrancer Arc Renji trains Chad using his bankai at the behest of Urahara. Though he was initially reluctant, Renji started to enjoy training him as it gave him a chance to fight. At the end of their training Sado is grateful for Renji's help, and the two gain a mutual respect for each others fighting ability. Renji expresses concern for his safety after his defeat, agreeing with Uryū to hurry and save him and Rukia.

Uryū Ishida
Renji first fights Uryū early into the series. Ishida tries to protect Rukia, and their fight goes unseen but ends with Ishida injured and defeated. He held no grudge for this defeat, probably because he was just like any other shinigami. They have very little interaction outside of the Bount Arc after this, until Orihime Inoue is kidnapped. During the Hueco Mundo Arc, Renji is about to be killed by Szayel's elite fraccion, when Ishida intervenes just in time. The two are shown to be an effective duo, almost defeating the Espada while having no use of their abilities, and Renji tried desperately to save him from a seemingly fatal attack (Szayel ripping Uryū's voodoo doll in half.) Ishida has been shown to be a valuable ally and friend for the shinigami.

Trivia

 * Renji's Zabimaru has been turned into a usable weapon in Dragonfable, along with Ichigo's Zangetsu.
 * Even though Renji's spiritual level is at that of about a captain's, he is not in the same league as one, similar to Ikkaku.
 * Renji has used his Bankai a total of 3 times within the manga, but has used it 5 times in the anime (8 if you include the films.) This of course excludes when he was training Chad, because this was simply training, not real fighting.
 * Renji is the first character in Bleach to be seen consciously materializing, and subsequently conversing with, their Zanpakutō's spirit.