Max Tennyson (BTR)

Maxwell Tennyson, called Grandpa Max by his grandchildren, or simply Max within the episodes, is a character in Ben 10: Revamped. Much of his past is unknown, and he has so far (in the pilot) played only a small role.

Answers
He has so far only appeared in the forest on a family camping trip with Ben and Gwen. He seems to be hiding something, based on his knowledge that Ben was specifically an alien rather than some generic monster (which totally isn't a copy of the original series pilot :P). His and Gwen's warning to Ben to not mess with the Omnitrix was ignored, and Ben actually figured out some new features.