Guardian Naga

If it dies, the guardian naga returns to life in 1d6 days and regains all its hit points.
Only a Wish spell can prevent this trait from functioning.

The naga is an 11th-level spellcaster. Its spellcasting ability is Wisdom (spell save DC 16, +8 to hit with spell attacks), and it needs only verbal components to cast its spells. It has the following cleric spells prepared:
Cantrips (at will): mending, sacred flame, thaumaturgy
1st level (4 slots): command, cure wounds, shield of faith
2nd level (3 slots): calm emotions, hold person
3rd level (3 slots): bestow curse, clairvoyance
4th level (3 slots): banishment, freedom of movement
5th level (2 slots): flame strike, geas
6th level (1 slot): true seeing

Melee Weapon Attack: +8 to hit, reach 10 ft.. Hit: 8 (1d8 + 4) piercing damage.
The target must make a DC 15 Constitution saving throw, taking 45 (10d8) poison damage on a failed save, or half as much damage on a successful one.

Ranged Weapon Attack: +8 to hit, range 15/30 ft.. Hit: The target must make a DC 15 Constitution saving throw, taking 45 (10d8) poison on a failed save, or half as much damage on a successful one.