Fey Ancestry. Therzt has advantage on saving throws against being charmed, and magic can't put Therzt to sleep.
Sunlight Sensitivity. While in sunlight, Therzt has disadvantage on attack rolls, as well as on Wisdom (Perception) checks that rely on sight.
Innate Spellcasting. Therzt's innate spellcasting ability is Charisma (spell save DC 10). Therzt can innately cast the following spells, requiring no material components:
At will: dancing lights
1/day each: darkness, faerie fire
Club. Melee Weapon Attack: +2 to hit, reach 5 ft., one target. Hit:2 (1d4) bludgeoning damage.