Void Avatar Prana

This Charm, from the Manual of Exalted Power: Abyssals, feels like it needs some fixing.

As is usual with changes I want to make, I am looking for a way to change it as little as possible and have it still work.

Change Type to Permanent.

Change Duration to One action/Instant.

Then, as-written/interpreted:

It can be used to protect you during the activation of Dark Messiah Form, in which case it lasts for that action only.

Alternately, it can be reflexively applied to supplement a single hand-to-hand attack, in which case the duration is the instance of that attack only.

Second Attempt

Turn the Charm into a Reflexive Charm and give it the Counterattack keyword. The Charm then could boost an attack (at an extreme expense) or be used as a defense/counterattack. This needs work. I am just recording the basics of the idea here.

I kind of like this approach. The question then becomes: Is 1 mote + 1 Willpower per use expensive enough for a Charm that can either be used to supplement a single attack's damage OR perfect defend from a single attack while making a potential counterattack (if the attacker actually touches the user)?