The True God: 10/Day. If the D.M. is reduced to 0 HP, they instead gain the effects of Power Word Heal. For the purpose of antimagic fields, this is not magical.

Magic Resistance. You have Advantage on saving throws against spells and other magical effects.

Reactive: The D.M. has 3 reactions instead of one.

Powerful Presence: all things within 120 feet are aware of the D.M., and how they respond is up to the DM (the real thing).

Legendary Resistance: (10)

Person Not Monster: This person is an NPC, not a monster. The main reason is that, to quote the Monster Manual," a monster is something that can be fought and killed." You don't kill the D.M. They kill you.

Charm Aura: all monsters or NPCs within 120 feet are charmed. If their Int is more than 3. This trait bypasses immunity to the charmed condition.

Spellcasting. The D.M. is a 100-level spellcaster. Its spellcasting ability is Cha (spell save DC 36, +29 to hit with spell attacks). The D.M. has the following spells prepared:

Cantrips (at will): Shocking Grasp, Acid Splash, Chill Touch, Control Flames, Create Bonfire, Dancing Lights, Druidcraft, Eldritch Blast, Fire Bolt, Frostbite, Guidance, Gust, Light, Magic Stone Mending, Minor Illusion, Mold Earth, Poison Spray, Produce Flame, Ray of Frost, Mage Hand

1st level (17 slots): Identify, Magic Missile, Divine Smite, Guiding Bolt, Inflict Wounds, Dissonant Whispers, Chromatic Orb, Thunderwave, Ray of Sickness, Hellish Rebuke 

2nd level (16 slots): Misty Step, Spiritual Weapon, Shining Smite, Moonbeam, Dragon's Breath, Shatter, Snilloc's Snowball Swarm, Aganazzar's Scorcher, Flame Blade, Flaming Sphere, Scorching Ray

3rd level (16 slots): Fireball, Spirit Guardians, Vampiric Touch, Call Lightning, Glyph of Warding, Lightning Bolt, Erupting Earth, Tidal Wave, Wind Wall, Conjure Animals, Animate Dead

4th level (15 slots): Banishment, Blight, Charm Monster, Compulsion, Confusion, Conjure minor elementals, Mordenkainen's faithful hound, Death Ward, Evard's Black Tentacles, Freedom of Movement

5th level (15 slots): Banishing Smite, Bigby's Hand, Cloudkill, Commune with Nature, Cone of Cold, Contact Other Plane, Contagion, Dispel Evil and Good, Geas, Mislead

6th level (14 slots): Heroes' Feast, Blade Barrier, Chain Lightning, Contingency, Create Undead, Disintegrate, Drawmij's instant summons, Find the Path, Forbiddance, Globe of Invulnerability

7th level (14 slots): Plane Shift, Delayed Blast Fireball, Divine Word, Etherealness, Finger of Death, Mirage Arcane, Prismatic Spray, Wall of Force, Resurrection

8th level (13 slots): Clone, Abi-Dalzim's Horrid Wilting, Antimagic Field, Befuddlement, Demiplane, Incendiary Cloud, Mind Blank, Power Word Stun, Sunburst

9th level (13 slots): Gate, Meteor Swarm, True Resurrection, Wish, Weird, Imprisonment, Power Word Kill, Power Word Heal, Prismatic Wall

Multiattack: The D.M. makes four longsword and four heavy crossbow attacks

Longsword Attack: Melee Weapon Attack: +30 to hit, reach 10 ft., 1 target. Hit: 15 (1d10 + 10) slashing damage.

Crossbow, Heavy Attack. Ranged Weapon Attack: +30 to hit, Range 100/400 ft., 1 target. Hit: 15 (1d10 + 10) piercing damage.

Command Monster: The D.M. gives a command to the monsters charmed by them.

Rebuttle: The D.M. goes no, and one thing that a person is attempting fails. Example player: "Can I climb the rock wall?"                                                                                                   DM "You can try."                                                                                                                       Player rolls a d20: "19"                                                                                                                           DM "You start to climb the rock wall, but the D.M. looks down at you and goes "No," you fall off the cliff and take 10 (3D6) Bludgeoning damage."

 Multiattack: The DM makes a multiattack instead of a one attack for an opportunity attack 

Legendary Action Uses: 10. Immediately after another creature’s turn, the D.M. can expend a use to take one of the following actions. The D.M. regains all expended uses at the start of each of its turns.

Spell Attack (Costs 1 Action): The D.M. casts a spell

Multiattack (Costs 2 Actions). The D.M. makes one multiattack

Command Monster (Costs 3 Actions): The D.M. gives a command to the monsters charmed by them.

Mythic Action Uses: 1. Immediately after another creature’s turn, the D.M. can expend a use to take the following action.

Rockfall (Costs 1 Actions). Rocks fall, you all die