A 60 ft radius around the demilich is at all times an antimagic field can not be disspelled.

All creatures within the 1 mile radius of the demilich lair can not heal unless the demilich chooses for them to be allowed to heal.

All creatures with in the 1 mile radius of the of the demiliches lair can not magically travel of creatures the demilich hasn't authorized. Such creatures can't teleport into or out of the tomb's area or use planar travel to enter or leave it. Effects that allow teleportation or planar travel work within the tomb as long as they aren't used to leave or enter the tomb's area. Also all spell or otherwise that allow communication with your deity are cut of while you are in this effect area unless the demilich deems otherwise, this means worlock and clerics cant use there spell that are from there patron / deity.

a non-evil creature enters the tomb's area, the creature takes 16 ( 3d10) necrotic damage.

your natural armor is AC20.

You are resistant to slashing, bludgeoning, and piercing damage (magic). Your resistant to lighting, and cold damage.

You are immune to all non magical slashing, piercing, and bludgeoning damage. Your also immune to disease, poison, charmed, exhaustion, paralyzed, poisoned, necrotic, and frightened.

3 times a day use If the lich fails a saving throw, it can choose to succeed instead.

As long a the demilich phylactery is still intact the demilich will reappear in 1 day but can not leave its lair / location of the phylactery within 1 mile.

The spells mage hand, prestidigitation, ray of frost, detect magic, magic missile, shield, thunder wave, acid arrow, detect thoughts, invisibility, mirror image, animate dead, counterspell, dispel magic, fireball, blight, dimension door, cloud kill, scrying, disintegrate, globe of invulnerability, finger of death, plane shift, dominate monster, power word stun, power word kill, levitate, and detect thoughts without needing materials to cast. Levitate and detect thoughts don’t use spell slots.

The demilich has immunity to any effect that turns undead.

If the demilich is subjected to an effect that allows it to make a saving throw to take only half damage, it instead takes no damage if it succeeds on the saving throw, and only half damage if it fails.

The demilich emits a bloodcurdling howl. Each creature within 30 feet of the demilich that can hear the howl must succeed on a DC: 15 Constitution saving throw or drop to 0 hit points. On a successful save, the creature is frightened until the end of its next turn.

The demilich targets up to three creatures that it can see within 10 feet of it. Each target must succeed on a DC: 19 Constitution saving throw or take 21 (6d6) necrotic damage, and the demilich regains hit points equal to the total damage dealt to all targets.

add +2 to one and +1 to another trait

You know Deep speech, undercommon, telepathy 12 ft out, plus five additional languages.

You have 120ft of truesight.

Where the demilich dwells it can as a bonus action cause 60 ft around it to tremble causing all walking creatures that are on the floor to succeed on a DC 19 Dexterity saving throw or be knocked prone.