Aethelhelm

Spellcasting. The necromancer is a 12th-level spellcaster. Its spellcasting ability is Intelligence (spell save DC 15, +7 to hit with spell attacks). The necromancer has the following wizard spells prepared:

Cantrips (at will): chill touch, dancing lights, mage hand, mending

1st level (8 slots): false life,* mage armor, ray of sickness*,  detect magic, magic missile, shield, thunderwave

2nd level (5 slots): blindness/deafness,* ray of enfeeblement,* web, detect thoughts, invisibility, mirror image

3rd level (5 slots): animate dead,* bestow curse,* vampiric touch*, animate dead, counterspell, dispel magic, fireball

4th level (5 slots): blight,* dimension door, stoneskin

5th level (4 slots): Bigby’s hand,  cloudkill, scrying

6th level (3 slot): circle of death*, disintegrate

*Necromancy spell of 1st level or higher

Grim Harvest (1/Turn). When necromancer kills a creature that is neither a construct nor undead with a spell of 1st level or higher, the necromancer regains hit points equal to twice the spell’s level, or three times if it is a necromancy spell.

Withering Touch. Melee Spell Attack: +7 to hit, reach 5 ft., one creature. Hit: 5 (2d4) necrotic damage.

Aethelhelm can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature’s turn. The lich regains spent legendary actions at the start of its turn.

Cantrip. Aethelhelm casts a cantrip.

Paralyzing Touch (Costs 2 Actions). Aethelhelm  uses its Paralyzing Touch.

Disrupt Life (Costs 3 Actions). Each non-undead creature within 20 feet of Aethelhelm must make a DC 18 Constitution saving throw against this magic, taking 21 (6d6) necrotic damage on a failed save, or half as much damage on a successful one.

4 legendary resistences