Grand Fisher

is a Hollow that had evaded Shinigami for 54 years and is responsible for the death of Ichigo Kurosaki's mother, Masaki.

Appearance
In his Hollow form, he resembles a giant hamster with bird-like hands and feet and a tentacle-like limb that hangs from his forehead, similar to the esca (lure) of an anglerfish. The lure is vaguely Human-sized and can be transformed to resemble anyone Grand Fisher wishes, usually taking the appearance of a young girl. It can act independently of Grand Fisher, and as long as either the lure or Grand Fisher himself survives, he cannot be purified.

In his first Arrancar form, he resembles a smaller, more humanoid version of his old self with a tattooed face. His mask remnants consist of his entire lower jaw, which obscures half of his face.

When he appeared in the Human World again to kill Ichigo, however, his appearance changed drastically. His entire mask was left unbroken and the upper half sat on his forehead. He also had fur all over his body and was much larger. His Hollow hole was also higher than his previous appearance. He carries a large Zanpakutō on his back. These changes to his appearance have not been explained.

Agent of the Shinigami arc
After his defeat by Ichigo Kurosaki, Grand Fisher returns to Hueco Mundo, where he is seen being patched up by the Arrancar Iceringer, while another Arrancar Di Roy Linker scolds him for running away from a Shinigami before even using all of his strength. Iceringer the shatters his mask and turns Grand Fisher into an imperfect Arrancar.

Arrancar arc
When the Grand Fisher is about to attack Kon in Ichigo's body the talisman Isshin gave Ichigo is thrown in between the two creating a barrier in between them. Isshin then appears dressed as a Shinigami and berates Ichigo for not wearing the talisman although he told him to where-ever he went. He then addresses the Grand Fisher as "Mr. Hollow" and says that Ichigo is not home and suggest that he "plays" with him instead When the Grand Fisher questions who he might be, Isshin apologize and introduce himself. Hearing the name Kurosaki, the Grand Fisher realizes that Isshin is the father of Ichigo and Isshin confirms this.

When the Grand Fisher realizes that Ichigo is the son of a Shinigami and therefore the real thing, he notes how he finally understands how he lost to him. He also states that he has no interest in Isshin and that he only came to kill Ichigo and orders Isshin to hand him over. Isshin, however, reveals that he does not know where Ichigo is because Ichigo is no longer a kid. He then explains that even if the Grand Fisher has no interest in him, he himself came to kill the Grand Fisher.

The Grand Fisher only begins to laugh and questions if they believe that he is nothing but a regular Hollow and transforms, growing in stature. A shocked Kon says that he is larger than a Menos Grande, which Grand Fisher takes as an insult. Isshin reveals that he is an Arrancar, a Hollow who had removed his mask to gain Shinigami powers. The Grand Fisher draws his Zanpakutō, saying that the size of a sword shows the amount of power someone may have and says that Isshin cannot win with his twig sized sword. Isshin smiles and challenges the Grand Fisher to give it a try and draws his own Zanpakutō and the two clash. He kills the Arrancar with a single cut from his sword.

Isshin states that all captain-level Shinigami know how to compress their Zanpakutō; otherwise all captains of the Soul Society would be swinging around swords the size of skyscrapers much like the Grand Fisher was doing and tell him to remember; never to judge an opponent by the size of their Zanpakutō. He then calls him a kid and says that he should not talk about a Shinigami's strength until he could understand that.

Hollow Form
Spiritual Power: Grand Fisher possesses enough spiritual power to fight Ichigo with ease, blocking his Zanpakutō with his hand and inflicting severe injuries on him.

Limb and hair growth: Grand Fisher displays the ability to extend his limbs and fur in order to attack, impede or restrain an opponent.

Lure: Grand Fisher typically hides his body and uses a lure that protrudes from his neck to attract potential victims. It can also be transformed into a decoy copy of someone close to his enemy's heart, allowing him to keep the enemy from attacking, as they will be unwilling to harm the decoy. The lure can be disconnected from the main body.

Memory probe: Using extensions hidden inside the fingers of one of his claws, Grand Fisher can pierce an opponent's body and look into their memories, searching for something that the enemy cannot cut. Then, with the other hand, he transforms his lure into that something.

Second body: The lure also functions as a second body for Grand Fisher. Grand Fisher states that both the lure and himself are his real body and when one is injured, it can jump into the other body.

Regeneration: He has shown the ability to regenerate at a somewhat high speed. When his hand is cut off by Ichigo, Grand Fisher's fur covers the injury and takes the form of the missing appendage. A new hand then emerges from the fur. He only exhibits this ability in his original Hollow form.

Arrancar Form
Transformation: The Grand Fisher demonstrates the ability to change his form when confronting Isshin. He grows greatly in size, with horns jutting out from his shoulders. He describes this as his true strength.

Zanpakutō: Grand Fisher has a Zanpakutō about the size of a two-story building with a rectangular tsuba. He did not try to release it and he was killed shortly after drawing it. It is unknown if this imperfect Arrancar had a Resurrección.

Appearances in Other Media
Grand Fisher is an unlockable character in Bleach: Dark Souls, in his Hollow form. One of the strongest characters in the game, his very powerful Hair Extension attack could cover 3 other opponents and slicing their health gauge in half or more.

Trivia

 * In the anime, he prefers to eat women, which is why he killed Ichigo's mother; in the manga, he prefers to eat children, and Ichigo's mother merely got in the way.