Archmage Mordenkainen

Legendary Resistance (5/Day). If Mordenkainen fails a saving throw, he can choose to succeed instead.

Special Equipment. Mordenkainen wields a staff of the magi, and a crystal ball. He wears bracers of defense, an ioun stone of fortitude, and a ring of protection(bonus to Saving Throws not included in stats). He carries a carpet of flying with him (6 ft. by 9 ft.).

Magic Resistance. Mordenkainen has advantage on saving throws against spells and other magical effects, and can use cantrips as a reaction during attacks of opportunity.

Observant. If Mordenkainen can see a creature's mouth while it is speaking a language he understands, he can interpret their words by reading their lips. Additionally, he gains a +5 bonus to his passive Wisdom (Perception) and Intelligence (Investigation) scores.

Spellcasting. Mordenkainen is an 20th-level spellcaster. His spellcasting ability is Intelligence (spell save DC 22, +16 to hit with spell attacks). Mordenkainen has the following wizard spells prepared:

Cantrips (at will): fire bolt, light, mage hand, prestidigitation, shocking grasp

1st level (5 slots): detect magic, mage armor*, magic missile, shield

2nd level (4 slots): mirror image, misty step, web

3rd level (4 slots): counterspell, fly, lightning bolt

4th level (4 slots): fire shield, dimension door, stoneskin*

5th level (4 slots): cone of cold, modify memory, Bigby's hand

6th level (2 slot): chain lightning, disintegrate

7th level (2 slot): Mordenkainen's Sword, Mordenkainen's magnificent mansion

8th level (2 slot): feeblemind, mind blank*

9th level (2 slot): time stop, wish

*Mordenkainen casts these spells on itself before combat.

Staff of the Magi. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 1d6+2 bludgeoning damage, or 1d8+2 bludgeoning damage if wielded with both hands.

The staff has 50 charges for the following properties. It regains 4d6+2 expended charges daily at dawn. If Mordenkainen expends the last charge, roll a d20. On a 20, the staff regains 1d12+1 charges.

Spells. While holding the staff, Mordenkainen can use an action to expend some of its charges to cast one of the following spells from it, using his spell save DC and spellcasting ability: conjure elemental(7 charges), dispel magic(3 charges), fireball(7th-level version, 7 charges), flaming sphere (2 charges), ice storm (4 charges), invisibility (2 charges), knock(2 charges), lightning bolt (7th-level version, 7 charges), passwall (5 charges), plane shift(7 charges), telekinesis(5 charges), wall of fire(4 charges), or web (2 charges).

Mordenkainen can also use an action to cast one of the following spells from the staff without using any charges: arcane lock, detect magic, enlarge/reduce, light mage hand, or protection from evil and good.

Retributive Strike. Mordenkainen can use an action to break the staff over his knee or against a solid surface, performing a retributive strike. The staff is destroyed and releases its remaining magic in an explosion that expands to fill a 30-foot-radius sphere centered on it.

Mordenkainen has a 50 percent chance to instantly travel to a random plane of existence, avoiding the explosion. If he fails to avoid the effect, Mordenkainen takes force damage equal to 16 × the number of charges in the staff. Every other creature in the area must make a DC 17 Dexterity saving throw. On a failed save, a creature takes an amount of damage based on how far away it is from the point of origin, as shown in the item description. On a successful save, a creature takes half as much damage.

Mordenkainen can take 5 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. Mordenkainen regains spent legendary actions at the start of his turn.

Cantrip. Mordenkainen casts a cantrip.

1st Level Spell (2 Actions). Mordenkainen casts one of his 1st level spells.

2nd Level Spell (3 Actions). Mordenkainen casts one of his 2nd level spells.