Tribulation of the stars

This spell is most effective at nighttime or in dim/dark places. As an action, any amount of your Health points sacrificed for any attack, checks, saves of your choice towards any creature of your choice. You can choose to either add or take away any half of what you sacrificed.

If this is activated during day it also gives you minus 1/3 or the enemy plus 1/3 of what you sacrificed, If the Enemy is in a dark or dim area whatever health you took away from yourself the decreased attack, checks, saves of your choice add minus 2 points each round until it dispels. 

At Higher Levels. 2-When surprise attacked the ability will auto activate for the damage you have taken instead of sacrificed. The spell increases lasting time by 1 round by each level.