Rocket Racoon

Rocket is generally less event focused than most heroes, but this build tries to minimize the amount of additional setup you have to do before he's online. Between Tinkering, "Murdered You!", and Knowhere, you should be drawing through your deck fairly quickly.

Knowhere combos with Starhawk to guarantee damage, thwart, and card draw every turn for only 2 resources. Once you have this 2 card combo assembled, keep it around because outside of a Rocket Launcher on a massive board, nothing else in the deck matches its efficiency. The fact that Starhawk's 2 damage can often help get minions low enough for you to trigger "Murdered You!" is just icing on the cake.

Between Thruster Boots and Specialized Training, Rocket will have 4 Thwart which makes the readies from C.I.T.T., Ever Vigilant, and I've Got a Plan very valuable. While you won't always be in a position to play or capitalize on Specialized Training during the first pass through the deck, you should generally play Thruster Boots as soon as you see it.

The thwarting package is actually robust enough that you should be safe to flip to alter-ego fairly often to take advantage of Tinkering. Energy Shield is very efficient fuel for Tinkering that can sometimes save you or Groot if you actually want to use the damage prevention.