Sources
CR
Type
Size
Alignment
Movement

Stolos

Medium Humanoid (any race), Neutral Evil

Armor Class 12, 15 with mage armor
Hit Points 91 (14d8 + 28)
Speed 30 ft., fly 30 ft.
STR
9
-1
DEX
14
+2
CON
15
+2
INT
12
+1
WIS
12
+1
CHA
18
+4
Saving Throws WIS +4, CHA +7
Skills Arcana +4, History +4
Damage Resistances psychic
Senses darkvision 60 ft., passive Perception 11
Languages any two languages, telepathy 30 ft.
Challenge 6 (2,300 XP)

Traits

Whispering Aura. At the start of each of Stolos's turns, each creature of its choice within 5 feet of it must succeed on a DC 15 Wisdom saving throw or take 10 (3d6) psychic damage, provided that the warlock isn't incapacitated.

Spellcasting

Innate Spellcasting. Stolos's innate spellcasting ability is Charisma. It can innately cast the following spells (spell save DC 15), requiring no material components:

At will: detect magic, jump, levitate, mage armor (self only), speak with dead

1/day each: arcane gate, true seeing

Spellcasting. Stolos is a 14th-level spellcaster. Its spellcasting ability is Charisma (spell save DC 15, +7 to hit with spell attacks). It regains its expended spell slots when it finishes a short or long rest. It knows the following warlock spells:

Cantrips (at will): chill touch, eldritch blast, guidance, mage hand, minor illusion, prestidigitation, shocking grasp

1st–5th level (3 slots): armor of Agathys, arms of Hadar, crown of madness, clairvoyance, contact other plane, detect thoughts, dimension door, dissonant whispers, dominate beast, telekinesis, vampiric touch

Actions

Talons. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit:8 (2d6 + 1) slashing damage.