[Fish Sandwich]

Kaixa.

I hate Kusaka's guts, but his dynamic with Takumi is just great, something that hasn't really been done since. Unlike most other not-title riders, Kaixa's not the kind of jerk who'll just start to get along with the main guy, oh no. Kaixa is the kind of jerk who becomes more and more of a bastard as the series goes on.
He and Takumi also they're riders from the start, which is also quite nice compared to the usual stuff (especially when dealing with Inoue, guy loves writing that stuff so much, he just gave the role to someone else.)

In fact, he's probably my favorite part of Faiz.