Spellcasting. Xarzith is a 10th-level spellcaster. His spellcasting ability is [+4] (spell save DC19, +11 to hit with spell attacks). Xarzith has the following Warlock spells prepared:
Cantrips (at will): Claws of Darkness, Eldritch Blast, Fire Bolt, Friends, Message, Mind Sliver, Poison Spray, Shocking Grasp, Thaumaturgy, Toll The Dead, True Strike
1st level (1/day): Hellish Rebuke, Mage Armor
2nd level (At Will): Alter Self, Invisibility (1/Day) Darkness
5th level (1/day) Contact Other Plane (2 slots): Burning Hands, Command, Contact Other Plane, Counterspell, Darkness, Detect Magic, Dispel Magic, Find Familiar, Fire Shield, Fireball, Geas, Hellish Rebuke, Hex, Hold Monster, Hold Person, Insect Plague, Mind Spike, Raulothim's Psychic Lance, Scorching Ray, Stinking Cloud, Suggestion, Summon Greater Demon, Wall Of Fire, Witch Bolt

Action Melee Attack. Hellfire Dagger: +7 to hit, reach 20/60 ft.,  (1d4 + 3) Piercing damage. (1d6+4) Radiant damage (True Strike). This weapon is fashioned from infernal iron and traced with veins of hellfire that shed dim light in a 5-foot-radius.,Any humanoid killed by an attack made with this weapon has its soul funneled into the River Styx, where it’s reborn instantly as a lemure devil.

Claws Of Darkness: +11 to hit, reach self/10 ft., (1d10) Cold damage. He shapes shadows into claws that grow from his fingers and drip inky blackness. The claws have a reach of 10 feet. While the spell lasts, he can make a melee spell attack with them that deals 1d10 cold damage.

Shocking Grasp: +11 to hit, touch, (2d8) Lightning damage. Lightning springs from him to a creature that he tries to touch. Make a melee spell attack against the target. On a hit, the target takes 1d8 Lightning damage, and it can’t make Opportunity Attacks until the start of its next turn. Cantrip Upgrade. The damage increases by 1d8 when you reach levels 5 (2d8), 11 (3d8), and 17 (4d8).

Unarmed Strike: +4 to hit, reach 5 ft., Hit: (1) Bludgeoning damage.

Action Ranged Attack. Witch Bolt: +11 to hit, range 60 ft., (6d12) Lightning damage.

Poison Spray: +8 to hit, range 30 ft., (2d12) Poison damage.

Fire Bolt: +8 to hit, range 120 ft., (2d10) Fire damage.

Scorching Ray +11 to hit, range 120 ft., (2d6) Fire damage. Count: 3

Eldritch Blast +11 to hit, range 420 ft., (1d10+4) Force damage. Count: 2

Other Actions.

Spells: Find Familiar, Contact Other Plane, Geas, Infernal Calling.

Dark One’s Blessing (Special)
When he reduces an enemy to 0 HP, he gains 14 Temp HP. He also gains this benefit if someone else reduces an enemy within 10 ft. of him to 0 HP.

Dark One’s Own Luck (Special)
When he makes an ability check or saving throw, he can add 1d10 to his roll. He can do this after seeing the roll but before any of the roll’s effects occur..He can use this feature 4 times per Long Rest, but no more than once per roll.

Magical Cunning (1 Minute)
Once per Long Rest, he can perform an esoteric rite for 1 minute, regaining up to 1 expended Pact Magic spell slots.

Ring of Mind Shielding
While wearing this ring, Xarzith is immune to magic that allows other creatures to read his thoughts, determine whether he is lying, know his alignment, or know his creature type. Creatures can telepathically communicate with him only if he allows it.

Actions In Combar. Two-Weapon Fighting.

Spells. Hex.

Actions In Combat. Opportunity Attack.

Spells. Hellish Rebuke, Counterspell.