Legendary Resistance (3/Day). If Jenna fails a saving throw, she can choose to succeed instead.
Battle Ready. When Jenna attacks with a magic weapon, she can use her Intelligence modifier, instead of Strength or Dexterity modifier, for the attack and damage rolls.
Warcaster. Jenna has advantage on CON saving throws that she makes to maintain her concentration on a spell when she takes damage. She can perform the somatic components of spells even when she has weapons or a shield in one or both hands.
Spellcasting. Jenna is an 18th-level spellcaster. Her spellcasting ability is Intelligence (spell save DC 19, +11 to hit with spell attacks). Jenna has the following wizard spells prepared:
Cantrips (at will): booming blade, mending, mage Hand, prestidigitation, fire bolt
1st level (4 slots): detect magic, identify, shield, magic missile*
2nd level (3 slots): warding bond, blur, heat metal, branding smite, invisibility, enlarge reduce
3rd level (3 slots): counterspell, conjure barrage, dispel magic, haste, revivify
4th level (3 slots): banishment, fire shield, fabricate, arcane eye
5th level (3 slots): dominate person, animate objects, scrying, creation
6th level (1 slot): globe of invulnerability
7th level (1 slot): simulacrum, power word: pain
8th level (1 slot): Incendiary cloud, earthquake
9th level (1 slot): time stop
Multiattack. The archmage can make 2 attacks per turn.
Staff of Torog. Melee Weapon Attack: +14 to hit, reach 5 ft, one target. Hit: 11 (1d6+8) bludgeoning damage. Once per turn, when you hit a target with the Staff of Torog, you can choose to either deliver an extra (4d6) force damage, or restore (4d6) hit points to a creature or object within 30 feet of the target.
Light Hammer +3. Melee or Range Weapon Attack: +14 to hit, reach 5 ft or range 20/60 ft, one target. Hit: 10 (1d4+8) bludgeoning damage.
Create Magic Turret. Jenna creates a floating magical turret of force within 30 feet of her that lasts for 1 minute. The turret acts on Jenna's initiative. The turret uses the Magic Missile spell once per turn. Jenna can have a maximum of 3 turrets at any one time.
Ball Bearing Bounce. As a bonus action, Jenna throws a ball bearing. She can then teleport up to 15 feet to the location of any ball bearing she can see.
Perform one of the following actions at initiative count 20 each turn.
Turn 1: Summon Steel Defenders. Jenna summons 1d6 Steel Defenders with the Improved Defender stat block into unoccupied spaces next to her. They then may move up to their movement speed. The Steel Defenders act as an ally of Jenna, they remain for 10 minutes, until they or Jenna dies, or until Jenna dismisses them as an action. In combat, the Steel Defenders shares Jenna's initiative count, but they take their turn immediately after hers.
Turn 2: Pain is Pleasure. Jenna holds the Staff of Torog up and slams it down. A wave of dangerous, violent energy ripples from her in all directions. All non-construct creatures within 60 ft must make a DC19 Constitution saving throw. They take (3d8) psychic damage on a failed save, or half as much damage on a successful one. Jenna revels in the collective pain, re-gaining hit points equal to half the combined damage taken.
Turn 3: The Crawling King. Jenna Shapechanges into a small Purple Worm.