Eldritch Ally

When you are in Great danger, you can quickly summon a monster to aid you.

Prerequisite(s): Arcane Battle Summoner, Augment Summoning, Spell Focus (conjuration), 4th-level Eldritch Knight

Benefit: Whenever an effect causes your Hit Points to be reduced to one quarter or fewer of their normal maximum amount, you can expend an unused spell slot as an immediate action in order to cast a summon monster spell of equal or lower level to the spell you expend. You do not provoke attacks of opportunity and do not need to use any spell components, unless the spell has costly material components, in which case the components are expended and they must be at hand.