Text: R (4+): Once per turn, before a control check is made, that control check gets -4. Failing this control check will not end the Combat Phase.
Akuma attempts to play a card.
Akuma decides he doesn't like that card, and decides to hack the control check for it. As a cost, he must make a control check of 4+
Akuma decides he doesn't like his ability either, so he decides he wants to hack the control check he is attempt to make. As a cost, he must make a control check of 4+.
Akuma decides he still doesn't like his ability, so he decides to hack that control check too. As a cost, he makes a control check ...
Since Akuma is never getting around to playing his ability, the "Once per turn" clause never activates. Akuma's self-hatred leads to him to (eventually) mill out.
Legal?