Shūkurō Tsukishima

is a mysterious individual who is capable of using Fullbring, and the former leader of Xcution.

Appearance
Tsukishima is a tall young man with long dark hair. He wears a long-sleeved collared shirt with suspenders and dark pants. He has a scar across his left eye.

Personality
As a person, Tsukishima appears to be cold, calm and collected in most things he does. He cuts down Uryū without much expression or effort and coolly admits to doing so without any hint of remorse. He also possesses some level of intelligence as he was able to organize and form a group while devising a plan to rid them of their powers.

History
Some time ago, Tsukishima gathered people with Fullbring abilities together, in order to find a way for them to erase their powers. He formulated the plan to pass their powers on to a Shinigami Representative, forming the group, Xcution. However, once this process began, he had a change of heart and used his abilities to kill the Shinigami Representative and those who had been relieved of their powers. Xcution's new leader, Kūgo Ginjō, has theorized that Tsukishima's new goal is to keep Ichigo Kurosaki away from them.

The Lost Substitute Shinigami arc
While Uryū Ishida is waiting outside of Ichigo Kurosaki's house, he spots Tsukishima standing on a nearby rooftop. Tsukishima leaves, causing Uryū to follow him. Using his speed, Tsukishima is able to catch Uryū off-guard and wound his right shoulder.

Sometime after his attack on Uryū, Tsukishima sends Moe Shishigawara to attack Orihime Inoue, but says that he does not need to do anything, because he believes that Shishigawara will not harm girls. As Shishigawara is about to fight Orihime, Tsukishima arrives and tells Orihime that he was the one who attacked Uryū.

Tsukishima introduces himself to Orihime, but Shishigawara interrupts their conversation, insisting that he will be able to take care of Orihime for him and tries to fight her. Tsukishima tells him to go home, but Shishigawara refuses. Tsukishima closes his book and reminds Shishigawara that he told him that he didn't need to do anything, and asks why he is still there. Shishigawara tells him that he wants to be useful to him. Tsukishima then casually remarks that he lost his page and takes out his bookmark, turning it into a sword. He asks Shishigawara if he minds taking responsibility for his lost page. Upon seeing the sword, Orihime asks him if it is a Zanpakutō. Tsukishima replies that it is not; it is actually his Fullbring, Book of the End. He tells Orihime that she can relax, as he does not plan to harm her at this time; instead, he is going to punish Shishigawara, who cannot follow his orders. Orihime moves herself in front of Shishigawara, which causes Tsukishima to remark that she is good-natured to the point where she does not like seeing even an enemy hurt. Orihime denies that being the reason; she informs him that since he attacked Uryū, she cannot let him leave. He merely replies that her reasoning is boring before turning away from her. When Orihime goes to use her powers, he attacks her from behind and appears to seriously wound her, however, she is shown without any damage moments later.

Moe sneezes on Tsukishima while he is eating a meal, prompting Tsukishima to pin him to the table with a fork and ask if he may continue speaking. He goes on to say that Moe no longer needs to do anything regarding Orihime and insists that he stop calling himself a henchman. Though Moe protests, Tsukishima says they already have her and there is no need of further contact. He then wonders whether to attack Yasutora Sado or Ichigo next, asking what Kūgo would say if he were to meddle with Ichigo directly.

Later, during Ichigo's training with Jackie Tristan, Tsukishima arrives at Xcution's base and cuts through it's door. Kūgo is shocked to see his arrival. Tsukishima remarks that its been a while since he saw the members of Xcution to which he hopes Giriko Kutsuzawa is not drinking too much and tells Yukio to read more. Kūgo demands to know why he came here for, but Tsukishima simply states that he cannot see Jackie or Riruka. Tsukishima spots the fish tank and presumes that is where they are hiding and Kūgo warns Tsukishima. Tsukishima attacks the fish tank and Kūgo yells at him not to, but it is already too late as the fish tank is already sliced in half. Suddenly, a burst of black energy comes out of the fish tank to which Tsukishima says is interesting as he sees Ichigo in a Shinigami's shihakushō formed from black energy.

Tsukishima observes Ichigo's appearance and compliments him on training while inside Riruka's Doll House, stating that he's surprised Ichigo has come so far in mastering his new abilities already. He is mockingly offended when Ichigo enquires his name, wondering why the members of Xcution hadn't informed the former Substitute Shinigami about him. Before he can finish introducing himself, he is attack by Sado who is trying to protect Ichigo. However, once Ichigo realizes his identity, after Tsukishima confirms he attacked Uryū and Orihime, they get into a brief fight. At first, Tsukishima compliments Ichigo's abilities but attacks him to show how incomplete they still are. He forces Ichigo's Fullbring to recede to the point he can't break his fall before Tsukishima moves in with a powerful strike. Before it can hurt Ichigo, Tsukishima is surprised to see his sword is blocked by that of Kūgo, which surprises him greatly.

Tsukishima then mocks Kūgo asking that if he is really trying to interfere to which Kūgo says that Tsukishima is the one who is interfering. Tsukishima tells Kūgo that if he fights him, he is most certainly going to die. They both then clash swords and fight. Kūgo tries to attack Tsukishima from above the head but he dodges this and attemps to cut Kūgo from below, Kūgo jumps up into the air and evades the attack and then unleashes an energy attack onto Tsukishima. Tsukishima comes out from the dust unharmed and manages to cut Kūgo across the right side of his face. Ichigo then jumps up and attacks Tsukishima from behind. This lightly burns his sword wielding arm. Tsukishima asks how Ichigo can evolve so well so quickly and comments that Ichigo is becoming much closer to the heights of his previous powers. Their conversation is then interrupted by Yukio, who uses his Fullbring to stop him from interacting with Ichigo. Tsukishima asks Yukio if it would not have been a better idea to lock him away instead. Yukio tells him that he is sorry to disappoint but he does not have enough batteries left to save him and that he did not save Ichigo for the reasons Tsukishima thought. Yukio then tells him that a crowd is starting to gather and someone is likely to see Tsukishima, which will be inconvenient for him. Riruka then shows up, holding her love gun to his back. He comments on it and Riruka says that he knows what it can do since he invented it. She then tells him to get lost and Yukio says they will be leaving and taking Ichigo with them and that Tsukishima should stay there if he wants to be exposed.

Powers & Abilities
Enhanced Speed: Tsukishima has remarkable speed; as noted by Uryū, his speed is far above that of a normal Human. Tsukishima is fast enough to attack the likes of Uryū, Orihime and Sado before they can even react.

Fullbring

 * Tsukishima's Fullbring manifests itself in his bookmark, which he can transform into a katana that has a bookmark-shaped tsuba. Kūgo Ginjō remarks that Book of the End is a sword with high attack capability that can literally cut through anything.

It has also been suggested that his Fullbring can also alter memories, however Ginjo comments that it doesn't.

Trivia

 * At the end of chapter 446, Tsukishima's sleeve on his right arm was burnt off a little by Ichigo's attack, but at the start of chapter 447 which continues on, his sleeve goes back to normal.