Shintarō

In life Shintarō is a Kishu dog kept by a girl named Miyuki. After death he degrades into a Hollow fused with the spirit of a Doberman Pinscher, the two joined into a single two-headed beast in which Shintarō forms the left head and the Doberman the right.

What defines Shintarō is a loyalty that outlasts even his humanity. Reduced to a mindless Hollow, he still recognizes Miyuki's frightened voice, and rather than harm her he turns the beast's left head against its own right head to shield the girl.

Shintarō once shared a large house with Miyuki and her parents. When the marriage fell apart and Miyuki moved with her mother into an apartment that barred pets, the dog stayed behind with her father, only to be killed soon after by a car right outside the home. He lingered on as a Plus among the living, and in time wore down into a Hollow, merging with the soul of another dog, a Doberman Pinscher.

During the Arrancar arc, Kon is placed by Rangiku Matsumoto inside a stuffed animal that Miyuki has named Shintarō after her lost pet. Discovering that the toy can move and talk, she befriends it, and it coaxes her into revisiting her old home. There the two are cornered in the yard by the two-headed Hollow. Kon tries to fight and is quickly beaten, and as the creature rounds on Miyuki she cries out Shintarō's name, prompting the left head to attack the right in her defense. Rangiku's arrival and purification of the creature finally lays bare its truth: the merged souls of Shintarō and the Doberman.