Pochita

Pochita (ポチタ) is a chainsaw devil.

Appearance
Pochita appears to be a small red canine with a chainsaw like appendage protruding from the center of his head.

Plot
Pochita initially met Denji after suffering wounds from an unknown source while Denji was visiting his mother's grave. In an act of empathy, Denji offered Pochita his blood so that he could recover from his wounds on the condition that the two would become partners. Pochita would live alongside Denji, assisting him in devil hunting and wood clearing while subsisting on whatever rations Denji could afford until, one day, both are mortally wounded by the zombie devil and his Yakuza turned zombies. Pochita would then enter Denji's body, assuming the role of his heart, while repairing Denji's damaged or missing organs and body parts in the process. Pochita is last seen communicating with Denji internally, communicating his wish that Denji show him more of his dreams in exchange for being his heart.

Abilities
Chainsaw Appendage: Protruding from Pochita's head is a chainsaw shaped appendage that functions as an actual chainsaw.

Blood Consumption-Based Healing: Pochita can heal his wounds by consuming human blood.

Body Assimilation: Pochita possesses the ability to fuse with a human body, assume the role of any missing organs, or seemingly replace damaged or missing organs. 

Relationships
Pochita was cared for by Denji. The two share a close relationship with each other.