Spell Sunderer

The Spell Sunderer is a subclass based on manipulating and disrupting the weave around them for short periods of time to better combat those with high magical potential, magical items, and magic abilities. They specialize in close-quarters combat with mages.

Bonus Proficiency

You gain proficiency in the Arcana skill

Magical Interference

At 3rd level, The Fighter gains the ability to disrupt magics within 50ft of them. As a reaction, the fighter can disrupt a spell that they can see being cast within range as long as the Fighter rolls above 10+spell level intelligence check. This functions differently than Counterspell as it doesn't count as a spell. The fighter can use this ability a number of times equal to their proficiency bonus per long rest.

Spell Siphon

Starting at the 7th level, the fighter's understanding of magic enables them to store their enemy's magical power within themselves and use it in their own attacks.

When the Fighter successfully disrupts a spell with the Magical Interference ability, they gain a Siphon Charge; the fighter can store a number of these charges up to their Intelligence modifier (minimum 1). The fighter can spend a charge to enhance an attack, turning the magic against their target. Each charge does 2d8 Force damage (increasing to 3d8 at the 11th level and 4d8 at the 17th level). These stacks dissipate on short or long rest.

Arcane Fortification

Starting at the 10th level, when the fighter rolls initiative and has no charges of Magical Interference remaining, they regain one charge.

Additionally, the fighter learns a new use for their Spell Siphon. Whenever the Fighter would take damage from a spell, they may use their reaction to spend a charge to reduce the damage. When spending a charge in this fashion, the fighter rolls their Spell Siphon dice, reducing the damage they take by the amount rolled.

Mana Seal

Starting at the 15th level, The fighter learns to bend and warp the weave around themselves, causing it to nullify magic in the area. The Fighter can use this ability equal to their Intelligence modifier number of times per day. The fighter must concentrate on this ability while it is active, making concentration checks as normal. 

Weave Shaper

Starting at the 18th level, The Fighter can detect spells from the weave's shaping itself, not requiring a visual cue to interrupt spells with the Fighter's Magical Interference ability. When using Magical Interference, The Fighter can force the spell's caster into making a Constitution save (dc 8+int+prof) on a success target takes half of the Magical Siphon damage, on fail damage as normal.

The Fighter learns how to take the magic stored by their Magical Siphon ability and imbue it into a magical weapon or armor of their choice. As an action, The Fighter can expend any number of charges stored by their magical siphon ability to imbue the magical item with an enhancement bonus equal to the number of charges expended. This ability lasts a number of rounds equal to The Fighter's Intelligence modifier. The Fighter may use this once per long rest.