Mikoto Inugami is the main antagonist of the story.
In Part 1, he attacks the SS.
In Part 2, He saves Banri Watanuki from a group of literal delinquents. He treats him as an 'underling' which Watanuki feels like a 'slave driver' because of that. Watanuki constantly buys him drinks and idolizes Mikoto. Soon, He becomes friends with Banri Watanuki.