While Diablo is exerted, the player can draw a card whenever an opponent does on their turn , potentially making him a draw power fiend in the right scenario
To fill up your graveyard, Celes, Rune Knight and Mog, Moogle Warrior arrive with potent effects that get creatures into your graveyard, with the Celes also being her own wincon and value engine with her ability to grow your whole board every time a creature enters from your graveyard
As Hecteyes's ability resolves, the next opponent in turn order (or, if it's an opponent's turn, that opponent) chooses a card in hand without revealing it, then each other opponent in turn order does the same
Most have experienced delays of weeks, if not months, in having these repaired