As a reaction, which you use when you are hit by an attack that you can see or take damage, you disappear from the world for a brief moment, entering the Astral Plane. The attack’s damage or the damage against you is halved and then you reappear at the space you occupied.
Astral Refuge. You can expend 1 additional mana to stay in the Astral Plane, returning to the space you occupied at the start of your next turn. You take advantage of the timeless nature of the Astral Plane, allowing you to use an action that only affects you.