my OCs Tatsuya and CROW
I think it's my first time introducing you CROW. So the redish guy is CROW, he is a demon(atm) and he basically chose Tatsuya to be the knight to his chess game. CROW has a frozen smile most of the time while Tatsuya lost all his facial expression when becoming CROW's knight. You can maybe notice that Tatsuya has a kind of necklace. Well that is the contract that makes him under CROW's control. If Tatsuya tries to express his emotion with his face (such as smile, tears, frowning), the mark expands and at some point captures the heart and crushes it. He isn't allowed to have emotions since the chess games doesn't consist in attacking the other group, but to kill each one of them. If he was to have a weak heart, this one would be crushed by the same weakness. And like all chess game, the game ends when they get the King: CROW.
ATM I'm not sure if I'm going to make a different condition for each player, but then I'll have to brainstorm this...