Stellar Resistance. When a creature you can see within 5 feet of you takes damage, you can use your reaction to grant that creature resistance to that damage. Once you use this property, you can't do so again until you finish a short or long rest.
Stellar Rebuke. When a creature hits you with a melee attack, you can use your reaction to cause the armor to flare with starlight. The attacker takes 3d10 + your proficiency bonus radiant damage. Once you use this property, you can't do so again until you finish a short or long rest.