Archmage Vathys Torlin of Klyreave Academy

Magic Resistance. The archmage has advantage on saving throws against spells and other magical effects.

Spellcasting. The archmage is an 20th-level spellcaster. Its spellcasting ability is Intelligence (spell save DC 19, +11 to hit with spell attacks). The archmage can cast invisibility and magnify gravity at will and has the following wizard spells prepared:

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

1st level (4 slots): detect magic, identify, mage armor*, magic missile

2nd level (3 slots): detect thoughts, immovable object, misty step

3rd level (3 slots): counterspell, fly, [spell]pulse wave/spell]

4th level (3 slots): banishment, gravity sinkhole, polymorph*

5th level (3 slots): cone of cold, scrying, wall of force

6th level (1 slot): gravity fissure, chain lightning

7th level (1 slot): teleport, plane shift

8th level (1 slot): mind blank*, reality break

9th level (1 slot): ravenous void

*The archmage casts these spells on itself before combat.

Legendary Resistance (3/Day). If Vathys fails a saving throw, he can choose to succeed instead. 

Branch of Astartes Melee Weapon Attack: +12 to hit, reach 5 ft., one target. Hit:  5 (1d8 +  3) bludgeoning damage plus 10 (2d8) force damage and the target must make a DC 19 wisdom save or be teleported  to an unoccupied space within 30 ft. of Vathys.

Cloak of Gravity. (3/Day). When a melee or ranged attack hits Vathys,  he may use his reaction to make the attack miss. Additionally, he may make one creature within 10 ft. of him make a DC 16 dexterity saving throw or take the damage from the attack.