Wisdom, Spell Save DC 17, Spell Attack Modifier +9
Duergar Resilience. The duergar has advantage on saving throws against poison, spells, and illusions, as well as to resist being charmed or paralyzed. Create Soulblade. As a bonus action, the duergar can create a shortsword sized, visible blade of psionic energy. The weapon appears in the duergar's hand and vanishes if it leaves the duergar's grip, or if the duergar dies or is incapacitated. Sunlight Sensitivity. While in sunlight, the duergar has disadvantage on attack rolls, as well as on Wisdom (Perception) checks that rely on sight.
Soulblade. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 3d6+3 force damage, or 4d6+3 force damage while enlarged. If the master manipulator has advantage on the attack roll, the attack deals an extra 1d6 force damage (5d6+3 force damage). Enlarge. For 1 minute the duergar magically increases in size, along with anything it is wearing or carrying. While enlarged, the duergar is Large, deals additional damage on its attacks (included in the attack), and makes Strength checks and Strength saving throws with advantage. If the duergar lacks the room to become Large, it attains the maximum size possible in the space available. Invisibility (Recharges after a Short or Long Rest). The duergar magically turns invisible for up to 1 hour or until it attacks, it casts a spell, it uses its Enlarge, or its concentration is broken (as if concentrating on a spell). Any equipment the duergar wears or carries is invisible with it.