Tokio "Bestial Choujin" Kurohara
About
Tokio was presumably born and grew up in the Yamato prefecture. As a small child, he and his classmates went on a field trip to a zoo, where they had to draw an animal that represented them. Tokio initially wanted to draw a lion, as he thought that they were cool and strong, but his peers decided to mock him by comparing him to a vulture, an animal that has negative undertones associated with it. They continued to bully him until he broke down into tears before running away. Later, his friend Azuma catches up to him and consoles him, and calls vultures "cool". This would later influence Tokio's choujin form that resembles a vulture.
(Source: Choujin X Wiki)