Spellsplinter

Spellsplinters have mastered one spell, Magic Missile, and bent their sorcery around it. Where other sorcerers shape magic into a different form each time, a Spellsplinter breaks it into fragments: more darts, harder hits, and a flick of the wrist that fires back whenever an enemy lands a blow.

As you grow in power, your darts multiply while Innate Sorcery burns, and a lucky roll can spawn another. Your darts can shatter into fire, frost, light, or shadow. At higher levels you can fire Magic Missile as a Bonus Action, and by the end you can pour Sorcery Points into each dart so it hits harder and pierces the defenses other casters rely on.

Spellsplinters are duelists and skirmishers, and they make terrifying rivals for wizards. They can be wild-magic prodigies, scholars who dissected a single spell for decades, or survivors whose power cracked the first time they were attacked and hasn't stopped since.

(Feedback welcomed)

Level 3: Magic Splinters

At 3rd level, you always have the Magic Missile spell prepared, and it doesn't count against your number of prepared spells. You can cast it at 1st level without expending a spell slot a number of times equal to your Charisma modifier (minimum of once). You regain all expended uses when you finish a Long Rest.

Level 3: Missile Splintering

At 3rd level, while your Innate Sorcery feature is active, Magic Missile creates a number of additional darts equal to half your Proficiency Bonus (round down). In addition, while your Innate Sorcery feature is active, when you cast Magic Missile and roll a 4 on any of its damage dice, you create one additional dart. This can happen only once per casting, and the additional dart can't trigger it again.

Level 3: Shattered Splinters

At 3rd level, when you finish a Short or Long Rest, you can choose Cold, Fire, Force, Necrotic, or Radiant. Until you finish another Short or Long Rest, the +1 damage of each dart of Magic Missile is of the chosen type. If you don't choose, the type is Force. The 1d4 damage of each dart remains Force. If you have the Greater Splinters feature, the extra damage it grants is also of the chosen type.

Cold

If you choose this option, the +1 damage of each dart, and the extra damage from Greater Splinters if you have it, is Cold damage.

Fire

If you choose this option, the +1 damage of each dart, and the extra damage from Greater Splinters if you have it, is Fire damage.

Force

If you choose this option, the damage remains Force.

Necrotic

If you choose this option, the +1 damage of each dart, and the extra damage from Greater Splinters if you have it, is Necrotic damage.

Radiant

If you choose this option, the +1 damage of each dart, and the extra damage from Greater Splinters if you have it, is Radiant damage.

Level 6: Coalesced Splinters

At 6th level, you can take a Reaction when a creature you can see within 120 feet of you hits you with an attack roll. You cast Magic Missile, expending a spell slot of 1st level or higher, and all of its darts must target that creature.

Level 14: Splinter Barrage

At 14th level, when you cast Magic Missile, it creates a number of additional darts equal to half your Charisma modifier (round down, minimum of 1).

You can cast Magic Missile as a Bonus Action a number of times equal to your Proficiency Bonus. You regain all expended uses when you finish a Long Rest. Normal rules for casting spells as a Bonus Action apply.

Level 18: Greater Splinters

At 18th level, as you cast Magic Missile, you can spend a number of Sorcery Points up to your Charisma modifier (no action required). Until the start of your next turn, each dart of Magic Missile you create deals extra damage equal to the number of Sorcery Points spent this way. This damage is of the type chosen with Shattered Splinters. For the duration, your Magic Missile darts ignore the Shield spell, and Counterspell cast using a spell slot of 5th level or lower can't counter Magic Missile.

If you use this feature again before the effect ends, the new bonus replaces the old one.