[Perdition]

Servant of a Dark Authority is a really cool passive that I think could be extended to curate and effect its promos rather than just Aquamancer. It'd mostly just be changing instances of light damage into dark damage. For heals, I think instead it could substitute the effect for an infliction-check poison that scales with the rank of the skill. For example, Graft would become a spell that targets enemies and inflicts a poison upon them with the LV increasing with your graft rank.

Holy spark would deal Dark and Lightning damage, Malmelo is sort of tricky, as the idea of an enemy team wide poison might be a bit much, but it would be infliction based and Malmelo itself has a 7 turn CD. Phoenix would be the same thing but within the area of effect, similar to Wretched Oil but without the damage aspect. But you see where I'm going with this.

Given Aquamancer establishes one can serve and draw their powers from a dark deity or higher power, I think allowing that to extend to the rest of curate would be nice so the class isn't restricted strictly to Mercalan worshippers.