When Nym deals damage to a creature with an attack or spell, he can use a Reaction to cause that creature to take extra psychic damage equal to his Charisma modifier and become frightened of him until the end of his next turn. He can use this feature once per Long Rest, unless he expends a Pact Magic spell slot to use it again.

Nym fires a bolt of crackling eldritch energy. Agonizing Blast adds his Charisma modifier to each beam's damage, while Repelling Blast can push a creature hit by a beam up to 10 feet away.

Nym marks a creature's mind with the storm demon's presence, potentially frightening it and dealing psychic damage through his patron's power.

When Nym reduces an enemy to 0 Hit Points, or an ally within 10 feet does so, he gains 17 temporary Hit Points.

Nym tears open a brief rift to the Lower Planes and hurls a defeated enemy's victim through hellish storm clouds, dealing 8d10 psychic damage and incapacitating the target on a failed Charisma save.

Nym knows nine eldritch invocations: Agonizing Blast, Armor of Shadows, Eldritch Mind, Pact of the Tome, Repelling Blast, Lessons of the First Ones, Mire the Mind, Otherworldly Leap, and Whispers of the Grave.

Nym uses Charisma as his spellcasting ability. He has three Pact Magic spell slots, all cast at 5th level, and regains them after a Short or Long Rest.

Once per Long Rest, Nym can perform a 1-minute ritual to regain expended Pact Magic spell slots equal to half his maximum, rounded up. This restores two spell slots.

Nym's patron is Vhalzareth, a storm demon of the Lower Planes. When Nym or an ally within 10 feet reduces an enemy to 0 Hit Points, Nym gains 17 temporary Hit Points.

Nym always has Burning Hands, Command, Scorching Ray, Suggestion, Fireball, Stinking Cloud, Fire Shield, Wall of Fire, and Geas prepared through his Fiend patron.

Nym gains one additional cantrip at this level and can replace one cantrip whenever he gains a Warlock level.

Nym can replace one eldritch invocation whenever he gains a Warlock level, provided he still meets all prerequisites.

Nym gains a sixth eldritch invocation.

Nym gains another Ability Score Improvement, represented by the Tough feat.

Nym can cast Contact Other Plane once per Long Rest to communicate with Vhalzareth. He automatically succeeds on the spell's saving throw.

Nym learns a fourth cantrip and gains a subclass feature.

Nym can choose one damage type when he finishes a Short or Long Rest. He has Resistance to that damage type until he chooses another. He can change the chosen type when he takes damage by expending a Pact Magic spell slot.

Nym gains Mystic Arcanum for one 6th-level spell, chosen as Mass Suggestion.

Nym gains an eighth eldritch invocation and another Ability Score Improvement, represented by the War Caster feat.

Nym gains Mystic Arcanum for one 7th-level spell, chosen as Forcecage.

Nym gains a ninth eldritch invocation and Mystic Arcanum for one 8th-level spell, chosen as Demiplane.

Nym can identify military rank, organization, and insignia, and can find temporary shelter and basic support among soldiers and veterans who recognize his service. He also retains the respect of those who served beside him, even when they distrust his pact.