Mutley

He is a giant wolf residing in a cave in Soul Society. He is the great-grandfather of Captain Sajin Komamura.

Appearance
He has the appearance of an extremely large wolf, which dwarfs a normal person. He has very long, dull white fur. He has a prominent scar on the top of his head, approaching his partially missing left ear.

Personality
He shows some level of pride, belittling Sajin when he returns home, and scolding him for being ashamed of and consequently hiding his appearance. He also believes his kind should not get involved in what is happening to Soul Society, a sentiment Sajin does not agree with.

The Thousand-Year Blood War arc
Sometime after the Wandenreich invasion of Soul Society, Sajin Komamura visits his great-grandfather in his cave. When Sajin greets him, he tells his great-grandson that he has guts to come back. Sajin prostrates himself and asks to inherit his family's secrets, which causes his great-grandfather to burst out laughing. He then insults his great-grandson for previously hiding his appearance and begging in front of him in such a manner. When Sajin says the world has changed and they no longer need to hide, the elder Komamura shouts at him, saying the world will stay the same regardless of who is in charge, they will hide as they have always done, and what happens is ultimately not their problem. When Sajin refuses to back down, he rises to his feet and states that he will crush him.

After they fight, the elder Komamura informs Sajin their family's secret technique: Humanification. He explains how his clan of wolfmen were originally cursed to dwell in the Beast Realm because of their sins in life. But, unable to accept their fate, they returned to Soul Society in a beast-like form. He reveals that they can temporarily recover the forms they once held and obtain great power in the process, but to do so they must offer up their own heart. He tells the startled Sajin to tear out his heart with his own hands and offer it to him in exchange for the technique. When Sajin does not respond, he states that the captain has no obligation to throw away his life for the Shinigami. Sajin insists that he has a duty to avenge the man who took him in when he fled the family he was taken in by and who was recently killed by the Quincy.

Sajin removes his heart, which is left in a dish. After Sajin leaves, the elder Komamura stares at the heart and contemplates Sajin's return to the clan and its ways. He thanks Sajin for what he has done for him and expresses his pride in him. He also notes that what Sajin feels is the same thirst for revenge that the captain had derided, but accepts this as revenge is the true nature of their clan. Commenting that Sajin's life as a Human will soon end and that he will become a vengeful beast, he says that he will drink of his hatred and again thanks him. He then reaches for the heart with his mouth.

Quotes

 * (To Sajin Komamura) "You seem to be a little confused. The world will not be destroyed. It will merely be controlled by different men. We will not change. No matter who seizes control of this world, we will live on, in the shadows."


 * (To Sajin Komamura) "It matters not to whom this world belongs. That is not our concern. Do you not see, Sajin? I am telling you not to disturb the peace of our kind. If you say you cannot do this, I will crush you underfoot."


 * (To Sajin Komamura) "Soon enough your life as a Human will end. You will become nothing more than a vengeful beast. Until the moment that happens, wallow in rage. Curse the world. Writhe in the throes of your vengeful heart. I will drink of your deep black hatred and it will sustain me once more. Ah, Sajin. Little Sajin. I must thank you for doing this for me. Thank you for struggling until you become a dumb beast all for my sake."