Font of Magic: Skek has 20 sorcery points that he regains after a long rest. Skek can use sorcery points to gain additional spell slots or sacrifice spell slots to gain additional sorcery points as a bonus action.
DarkVision
Fury of the Small: Once per short rest, you can deal 20 extra damage to a creature with a size larger than yours.
Nimble Escape
Tides of Chaos: Once per long rest, UrSkeksis gains advantage on one attack roll, ability check, or saving throw. This can be reset for 2 sorcery points.
Meta-Magic - Twinned, Empowered, Careful, Distant.
Controlled Chaos - Whenever you roll on the Wild Magic Surge table, you can roll twice and use either number.
Elemental Adept - Fire
Spellcasting. UrSkeksis is a 20th-level spellcaster. His spellcasting ability is 22 (spell save DC 20, +13 to hit with spell attacks). UrSkeksis has following Sorceror spells prepared:
Cantrips (at will): Control Flames, Fire Bolt, Friends, Gust, Mage Hand, Prestidigitation.
1st level (4 slots): Bane, Mage Armor, Magic Missile
2nd level (3 slots): Scorching Ray
3rd level (3 slots): Counterspell, Fireball
4th level (3 slots): Banishment, Polymorph, Wall of Fire
5th level (3 slots): Immolation
6th level (2 slots): Disintegrate
7th level (2 slots):
8th level (1 slots): Incendiary Cloud
9th level (1 slots): Power Word Kill
Legendary Resistance (3/Day). If the monster fails a saving throw, it can choose to succeed instead.
Call for Help (Costs 2 Actions). Skek calls for help, 2 Spined devils, and 1d6+1 hell wasps are summoned to his aide.
Multicast (Costs 3 Actions). Skek casts a 5th level spell or lower that could target one enemy, it targets 4 different enemies instead.