Perception +7
Fiends Sight 120 ft., Passive Perception 17
Demonic Shadows. The demon darkens the area around its body in a 10-foot radius. Nonmagical light can’t illuminate this area of darkness
Devour Soul. The demon can eat the soul of a creature it has killed within the last hour, provided that creature is neither a construct nor an undead. The devouring requires the demon to be within 5 feet of the corpse for at least 10 minutes, after which it gains a number of Hit Dice (d8s) equal to half the creature’s number of Hit Dice. Roll those dice, and increase the demons hit points by the numbers rolled. For every 4 Hit Dice the demon gains in this way, its attacks deal an extra 3 (1d6) damage on a hit. The demon retains these benefits for 6 days. A creature devoured by the demon can be restored to life only by a wish spell.
Magic Resistance. The demon has advantage on saving throws against spells and other magical effects.
Magic Weapons. The demons weapon attacks are magical.
Multiattack. The demon uses its Soul-Stealing Gaze and makes two attacks: one with its claws and one with its bite.
Claws. Melee Weapon Attack: +11 to hit, reach 5 ft., one target. Hit: 17 (2d10 + 6) slashing damage.
Bite. Melee Weapon Attack: +11 to hit, reach 5 ft., one target. Hit: 32 (4d12 + 6) piercing damage.
Soul-Stealing Gaze. The demon targets one creature it can see within 30 feet of it. If the target can see the demon and isn’t a construct or an undead, it must succeed on a DC 16 Charisma saving throw or reduce its hit point maximum by 13 (2d12) and give the demon an equal number of temporary hit points. This reduction lasts until the target finishes a short or long rest. The target dies if its hit point maximum is reduced to 0, and if the target is a humanoid, it immediately rises as a ghoul under the nabassu’s control.