Urbane Magician

Secret of Time’s End. Whenever the magician deals damage with a warlock spell, the target’s hit point maximum is reduced by the damage it took for 1 hour. If the magician reduces the target to 0 hit points, the magician gains 5 temporary hit points. If the magician reduces the target’s hit point maximum to 0, it dies.

Innate Spellcasting. The magician’s spellcasting ability is Charisma (spell save DC 13). It can innately cast the following spells:

At will: disguise self, mage armor

Spellcasting. The magician is a 6th-level spellcaster. Its spellcasting ability is Charisma (spell save DC 13, +5 to hit with spell attacks). The magician has following warlock spells prepared:
Cantrips (at will): chill touch, eldritch blast(pushes target 10 feet away), minor illusion
1st–3rd level (2 3rd-level slots): invisibility, identify, misty step, moonbeam, see invisibility, slow, [spell]suggestion

Multiattack. The urbane magician makes two weapon attacks.

Pact Rapier. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 5 (1d6 + 2) piercing damage plus 7 (2d6) force damage.

Magical Defiance. When a creature hits the magician with an attack, the magician casts a cantrip on the attacker or makes a weapon attack on it.