Colossus may be the only Hero with a 4 hand size that I want to play.
This is largely because he is the Marvel Champions equivalent of a Rottweiler. He is huge, he deals serious damage and he's a little goofy.
First of all, I want to call out Armor Up. This is the first time a card like this has appeared in Champions; the hero changes form because the villain activates. What makes this thematic is that whenever Colossus changes to hero form, he gains a tough status. So just by becoming a hero, Colossus prevents the villain from dealing damage to him.
Further, alter ego cards serve to bolster Colossus as a hero, and he has several methods of scouring the deck for Colossus upgrades. This matters a lot because the naked essence of Colossus are the tough status cards, which FFG recognized when they gave him a setup ability that digs out Organic Steel. Tough cards are such a massive part of Colossus' strategy that any control over those status cards is borderline OP.
But Colossus has several ways to burn cards in hand and his deck to dig out cards that provide Tough status or exploit it. This becomes his gameplay loop, as his deck has several cards with multiple copies to reduce randomness. Some people may find Colossus dull, since he is so singularly focused on Tough status, but once you embrace the Tough, Colossus becomes a ballet of hard choices that betrays a complexity to the character that I did not expect.