Innate Spellcasting. The soul monger's innate spellcasting ability is Intelligence (spell save DC 16, +8 to hit with spell attacks). It can innately cast the following spells, requiring no material components.

Fey Ancestry. The soul monger has advantage on saving throws against being charmed, and magic can't put it to sleep.   Magic Resistance. The soul monger has advantage on saving throws against spells, and other magical effects.   Soul Thirst. When the soul monger reduces a creature to 0 hit points, the soul monger can gain temporary hit points equal to half the creature's maximum hit point maximum. While the soul monger has temporary hit points from this ability, it has advantage on attack rolls.   Weight of Ages. Any beast or creature, other than Shadar-Kai, that starts it's turn within 5 feet has it's speed reduced by 20 feet until the start of the creature's next turn.