King Ars Primer+Immediate Actions+King_s_Castle

When an opponent makes a melee attack against an ally with this feat who is no farther away from you than half your land speed, as an immediate action you can move up to half your speed directly towards the ally. This movement provokes attacks of opportunity. As long as you end this movement adjacent to the targeted ally, you may take the attack in their place. The attack is resolved as though you were the original target of the attack, comparing the attack roll to your defenses and dealing damage as appropriate. You may invest essence into this feat, increasing your land speed by 5 feet per point of essence invested.

You gain 1 point of essence.