Auraryx, the Shard of Light

Aurora Field. Allies within 30 ft. gain resistance to one damage type, which changes at the start of each of the dragon’s turns. Roll 1d6
1 Fire, 2 Cold, 3 Acid, 4 Lightning, 5 Thunder, 6 Force

When Sihtric takes a lair action, the field dims and reactivates at the start of Auraryx’s next turn.

ON TURN — CHOOSE 1 ACTION

Radiant Lance. +13 to hit, range 120 ft., one target. Hit: 3d10 radiant damage plus 2d10 damage of a random type:
1 Fire, 2 Cold, 3 Acid, 4 Lightning, 5 Thunder, 6 Force

Blinding Flare. (Recharge 5–6). The dragon emits a radiant pulse in a 60-foot cone. Each creature in that area must make a DC 19 Constitution saving throw. On a failed save, the creature takes 5d10 radiant damage and is Blinded until the end of its next turn. On a successful save, the creature takes half damage and is not blinded.

One-Time Use — The Light Remembers.Trigger: An ally within 120 ft. drops to 0 HP. Effect: All enemies within 20 ft. of that ally must make a DC 18 Dexterity saving throw. Fail: 8d10 radiant damage. The ally stabilizes and regains 10 HP immediately.

Lightwarp Counter. Trigger: An ally within 60 ft. is targeted by a spell. Effect: The caster must make a DC 18 Constitution saving throw. On a failed save, the spell fizzles and has no effect (the spell slot is still consumed). On a successful save, the spell functions normally.