Tighten the Knot

As part of the Aegis Knotwork tattoo

Gain a reaction: When hit, you can tighten the knot to gain resistance to that attack’s damage type (applies to that instance only) and move 5 ft without provoking opportunity attacks.

You can use this reaction and number of times equal to you proficiency modifier, per long rest

Scaling: At lvl 17, when you trigger the reaction you also gain half cover until start of your next turn.