You can leverage your bonds of friendship for protection. When an attacker that you can see hits you with an attack, you can take a Reaction to gain a bonus to your Armor Class equal to the number of friendly creatures within 5 feet of you (to a maximum of +10), potentially causing the attack to miss you instead.
Once you use this feature, you can't use it again until you finish a Short or Long Rest. You can also restore your use of it by expending a level 2+ spell slot (no action required).