Gohan and Piccolo have one of the best relationships in Dragon Ball, and DBZ & Dragon Ball Super are the proof.

He is the reincarnation of King Piccolo, the main antagonist in Dragon Ball, but later becomes an important ally and part of the "Z warriors". While he may still be a bit grumpy, he's not evil ...

Piccolo has been a fixture of Dragon Ball since his introduction, consistently holding his own among the rest of the cast.