This is Ty and Volvar, two of the main characters for a story that I've been hoarding for too long.
Ty is secretly breaking the law in his basement, while under the cover of being the city's finest mechanic.
Volvar is a 'glower', a human-looking race with the power to control fire. He is spoiled and popular, but in one of the guilds that works to root out criminals in the city.
An unfortunate turn of events (involving a girl, of course!) forces the two to cooperate even though they can't get along for the life of them.