Dark Knight - Rework Concept
Edge/Flood of Shadow no longer cost MP. Instead, they drain the Dark Knight's HP an amount equivalent to a 200 potency heal, and replace the amount drained with a shield lasting 30s, subsequent uses increase the timer to a max of 60s. Any remaining shield is converted back into HP out of combat when the timer ends.
The Blackest Night (TBN) costs no MP, and increases the timer on shields from Edge/Flood by 30s, to a max of 60s.
Abyssal Drain & Carve and Spit each cost 3000 MP, and are on the GCD, not sharing a recast with each other. Abyssal Drain's heal is reduced to 100 potency due to the recast time. Carve and Spit applies a debuff to the target that is consumed to double the HP gain of the next Souleater combo.