Sources
CR
Type
Size
Alignment
Movement

Dancing Flame

Medium Fiend, Neutral Evil

Armor Class 15 (natural armor)
Hit Points 66 (12d8 + 12)
Speed 30 ft., fly 60 ft.
STR
8
-1
DEX
17
+3
CON
13
+1
INT
15
+2
WIS
12
+1
CHA
20
+5
Skills Deception +9, Insight +5, Perception +5, Persuasion +9, Stealth +7
Damage Resistances cold, fire, lightning, poison; bludgeoning, piercing, slashing, from nonmagical attacks
Senses darkvision 60 ft., passive Perception 15
Languages Abyssal, Common, Infernal, telepathy 60 ft.
Challenge 4 (1,100 XP)

Traits

Telepathic Bond. The flame ignores the range restriction on its telepathy when communicating with a creature it has charmed. The two don't even need to be on the same plane of existence.

Flame. The flame sheds bright light in a 20-foot radius and dim light for an additional 20 feet. If it leaves the hall or is reduced to 0 hit points, it is destroyed and can't re-form for 24 hours.

Actions

Claw. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit:6 (1d6 + 3) fire damage.

Charm. One humanoid the flame can see within 30 feet of it must succeed on a DC 15 Wisdom saving throw or be magically charmed for 1 day. The charmed target obeys the flame's verbal or telepathic commands. If the target suffers any harm or receives a suicidal command, it can repeat the saving throw, ending the effect on a success. If the target successfully saves against the effect, or if the effect on it ends, the target is immune to this flame's Charm for the next 24 hours.

The flame can have only one target charmed at a time. If it charms another, the effect on the previous target ends.

Draining Kiss. The flame kisses a creature charmed by it or a willing creature. The target must make a DC 15 Constitution saving throw against this magic, taking 32 (5d10 + 5) psychic damage on a failed save, or half as much damage on a successful one. The target's hit point maximum is reduced by an amount equal to the damage taken. This reduction lasts until the target finishes a long rest. The target dies if this effect reduces its hit point maximum to 0.