im wanting to make a class based around the comic book character spawn . id like some input on how thatd work such as what base class would suit him and so forth.
Definitely fiend pact warlock. Where you go from there is a bit more subjective and should be based on how you want to play him and what aspects you want to highlight/focus on.
Personally I think some shadow monk to go with it would be fun and thematically appropriate.