Generally worse than iron fist for same cost.

Iron fist does 2 stun+1 last hp block. He does 6 damage over 2 turns

Charlie does 1 block from toughness (can't attack first turn he comes out either)+1 last hp block. Charlie does 3 damage over 3 turns.

So Charlie has 1 fewer block, does 2 less damage over a longer period of time and has more conditions.

Only other best case scenario for Charlie (aside from other card combos) is blocking exactly 1 ATK hits (maybe from small Minions) and returning 1 damage each. Iron fist can't tank 5x 1 ATK hits while still doing 4 damage.

This card is extremely niche and in most games there will generally be better options. That being said after 3 years playing I’ve finally found myself needing to play him. I think his best/only usage comes from a 4 player Alliance strategy. He’s expensive enough to feel satisfying as a Joining Forces target, there are enough minions for his retaliate to be useful, and he sticks around long enough for Stand Together.