Sources
CR
Type
Size
Alignment
Movement

Hastain

Medium Celestial, Chaotic Evil

Armor Class 19 (glory)
Hit Points 82 (15d8 + 15)
Speed 30 ft., swim 30 ft.
STR
18
+4
DEX
15
+2
CON
12
+1
INT
19
+4
WIS
16
+3
CHA
24
+7
Saving Throws DEX +5, CON +4, WIS +6, CHA +10
Skills Arcana +7, History +7, Performance +10, Persuasion +10
Senses passive Perception 13
Languages Celestial, Common, Deep Speech, Draconic
Challenge 8 (3,900 XP)

Traits

Glory. Hastain's Armor Class includes its Charisma modifier.

Hold Breath. Hastain can hold its breath for 1 hour.

Special Equipment. Hastain wears a talarith.

Spellcasting

Spellcasting (Psionics). Hastain casts one of the following spells, requiring no spell components and using Charisma as the spellcasting ability (spell save DC 18):

At will: light, mage hand, prestidigitation

1/day each: mass suggestion, sending

2/day each: dimension door, phantasmal force

Actions

Multiattack. Hastain makes two Trident attacks.

Trident. Melee or Ranged Weapon Attack: +7 to hit, reach 5 ft. or range 20/60 ft., one target. Hit:7 (1d6 + 4) piercing damage, or 8 (1d8 + 4) piercing damage if used with two hands to make a melee attack, plus 3 (1d6) force damage if Hastain is wearing its talarith.

Chromatic Bolt. Ranged Spell Attack: +10 to hit, range 90 ft., one target. Hit:22 (5d8) damage of a type chosen by Hastain from the following list: cold, fire, lightning, or radiant.

Summon Duplicate (Recharges after a Short or Long Rest). Using its talarith, Hastain summons a duplicate of itself. The duplicate obeys the reigar's commands and uses the reigar's statistics, except it is an unaligned Construct that doesn't have a talarith of its own. The duplicate takes its turn immediately after the reigar. It vanishes after 1 hour or when it is reduced to 0 hit points.