25% chance to revive a random fallen ally. For each additional fallen ally, the chance increases by 10%. (If only one ally has fallen, the chance is 25%.)
The revived ally gains HP equal to 50% of the max HP of the enemy with the highest HP, and that enemy loses the same amount of HP. (Up to 1000 HP.)
If no ally is revived, the enemy still loses 50% of its max HP, and the caster gains that amount of HP.