Black Sage

Elementalist. Spells the Sage casts ignore resistance to cold, fire, & lightning damage. In addition, when they roll damage for a spell they cast that deals damage of that type, they can treat any 1 on a damage die as a 2.

Empowered Evocation. The Black Sage adds their Intelligence modifier to the damage rolls of any wizard evocation spells they cast.

Magical Resistance. The Black Sage has advantage on saving throws against spell and other magical effects.

Overchannel. When the Sage casts a wizard spell of 1st through 5th-level that deals damage, they can deal maximum damage with that spell.

The first time they do so, they suffer no adverse effect. If they use this feature again, they take 2d12 necrotic damage for each level of the spell, immediately after they cast it. Each time they use this feature again, the necrotic damage per spell level increases by 1d12. This damage ignores resistance and immunity.

Potent Cantrip. When a creature succeeds on a saving throw against the Sage's cantrip, the creature takes half the cantrip's damage (if any) but suffers no additional effect from the cantrip.

Sculpt Spells. When the Black Sage casts an evocation spell that affects other creatures that they can see, they can choose a number of them equal to 1 + the spell's level. The chosen creatures automatically succeed on their saving throws against the spell, and they take no damage if they would normally take half damage on a successful save.

Signature Spells. The Black Sage can cast the following spells at will without the use of a spell slot at their default level or material components:

Frost Fingers, Scorching Ray

Spellcasting. The Black Sage is a 21st-level spellcaster. His spellcasting ability is Intelligence (spell save DC 24, +16 to hit with spell attacks) and has the following spells prepared:

Cantrips (at will): Fire Bolt, Frostbite, Frost Fingers, Lightning Lure, Produce Flame, Ray of Frost, Shocking Grasp
1st level (4 slots): Chromatic Orb, Earth Tremor, Ice Knife, Shield, Witch Bolt
2nd level (3 slots): Ag's Scorcher, Earthbind, Earthen Grasp, Flaming Sphere, Misty Step, Scorching Ray, Rime's Binding Ice
3rd level (3 slots): Counterspell, Dispel Magic, Fireball, Fly, Haste, Lightning Bolt, Slow
4th level (3 slots): Banishment, Dimension Door, Elemental Bane, Fire Shield, Stoneskin, Storm Sphere, Wall of Fire, Watery Sphere
5th level (3 slots): Cone of Cold, Maelstrom, Steel Wind Strike, Wall of Stone
6th level (3 slots): Chain Lightning, Disintegrate, Flesh to Stone, Firaga
7th level (2 slots): Fire Storm, Mordenkainen's Sword, Thundaga, Whirlwind
8th level (1 slot): Blizzaga, Dark Star, Power Word Stun, Tsunami
9th level (1 slot): Blade of Disaster, Flare, Power Word Kill, Meteor Swarm
10th level (1 slot)

Spell Mastery. The Black Sage can cast the following spells once without the use of a spell slot at their default level or material components:

Fireball, Lightning Bolt

Unusual Nature. The Black Sage doesn’t require food or drink.

+3 Quarterstaff. Melee Weapon Attack: +12 to hit, reach 5 ft., 1 target. Hit: 10 (1d8 + 5) bludgeoning damage. 

+1 Light Crossbow. Ranged Weapon Attack: +11 to hit, range 80/320 ft., 1 target. Hit: 9 (1d8 + 4) piercing damage.