New Power ideas for Flare

New Power ideas for Flare

I have a few new ideas for powers. I am making my own campaign, could anybody give me help?

The first one is easy - Brute ability to slow enemies down. I did it easily.

Second one is for ranger - Did this fine as well, a shot that knocks enemies back.

The other one - for adept, is to use all mana and convert it into mental damage (200% at level 1, 450% at level 5) with a shot that will instantly kill most non-boss enemies. However, I cannot figure out how to make it deal damage dependent on the player's mana reserves and how to make it empy the player's mana regardless of level. Any help?