Magic Resistance. The yuan-ti has Advantage on saving throws against spells and other magical effects.

Multiattack. The yuan-ti archpriest makes three Bite or Radiant Burst attacks in any combination.

Bite. Melee Attack Roll: +7, reach 5 ft. Hit: 11 (2d6 + 4) Piercing damage plus 10 (3d6) Poison damage.

Radiant Burst. Melee or Ranged Attack Roll: +9, reach 5 ft. or range 60 ft. Hit: 27 (4d10 + 5) Radiant damage.

Constrict. Strength Saving Throw:  DC 15, one Large or smaller creature within 5 feet. Failure: 28 (7d6 + 4) Bludgeoning damage. The target has the Grappled condition (escape DC 14), and it has the Restrained condition until the grapple ends. Success: Half damage only.

Holy Word (Recharge 4–6). Wisdom Saving Throw: DC 17, each enemy in a 20-foot Emanation originating from the yuan-ti archpriest. Failure: 21 (6d6) Radiant damage, and the target has the Stunned condition until the end of the yuan-ti archpriest’s next turn. Success: Half damage only.

Spellcasting. The archpriest casts one of the following spells, requiring no Material components and using Wisdom as the spellcasting ability (spell save DC 17):

At Will: Light, Thaumaturgy
1/Day Each: Flame Strike (level 6 version), Greater Restoration, Raise Dead, Zone of Truth
3/Day: Suggestion

Divine Aid (3/Day). The priest casts Bless, Dispel Magic, Healing Word, or Lesser Restoration, using the same spellcasting ability as Spellcasting.