[@TheWindel]

Technically to allow the transformation to occur, one soul is consumed. And to maintain it, one soul is required for every 20 seconds in combat.

Out of combat 1 soul equates to 1 hour of transformation tine 

The mirror facilitates the transformation singularly. If perhaps I were to add something it would be that it deflects projectile attacks in both states.

Her overdrive forms are very stamina draining Rosea for instance will quickly tire physically. While Caligos Soul consumption increases to a single soul every five seconds.