Arcane Subnet

6th-level evocation

Casting Time: 1 action
Range: 120 feet
Components: V, S
Duration: Concentration, up to 1 minute

Description

You deploy a network of arcane nodes that turns the battlefield into a pressure-building magical siege engine. Magic destabilizes, movement feeds the system, and failure becomes fuel.

Effect

Choose a point within range. An invisible arcane subnet fills a 40-foot-radius sphere centered on that point. You create 6 arcane nodes at points you choose within the area (no two within 10 feet of each other).

Distributed Casting

While the subnet persists, when you cast a spell, you may originate it from any arcane node instead of your space. Spells cast this way ignore half cover and three-quarters cover.

If a spell you cast through a node fails, misses, or is countered, its energy is absorbed by the subnet instead of being wasted.

Spell Fragmentation

When a creature other than you casts a spell of 1st level or higher within the subnet, it must succeed on a Constitution saving throw.

• On a failure, the spell still resolves, but either its damage is reduced by one damage die or its duration is reduced by 1 round (DM’s choice).

• On a success, the spell functions normally.

Arcane Load

The subnet accumulates Arcane Load, representing increasing instability. It gains 1 Load whenever any of the following occur within the area:

• A spell of 1st level or higher is cast

• A spell is countered, dispelled, or otherwise fails

• A creature moves more than 15 feet during its turn

Siege Pressure

At the start of each of your turns while concentrating on this spell, choose one of the following effects, which lasts until the start of your next turn:

• Compression: Hostile creatures have their speed reduced by 10 feet.

• Instability: The next spell cast by a hostile creature has disadvantage on its attack roll or saving throw.

• Reinforcement: You gain advantage on your next spell attack roll or a +2 bonus to your spell save DC (your choice).

Subnet Collapse

As a bonus action on your turn, you may collapse the subnet, ending the spell and expending all accumulated Arcane Load. Choose one of the following effects:

• Force Discharge: Each hostile creature in the area takes 1d8 force damage per Load (Dexterity saving throw for half damage).

• Arcane Lockdown: Each hostile creature must make a Constitution saving throw. On a failure, it is restrained until the end of its next turn. On a success, its speed becomes 0 until then.

• Failsafe Reassembly: You and up to three allies of your choice gain temporary hit points equal to 5 × Load, and the next spell you cast within 1 round of 5th level or lower does not expend a spell slot.

Backlash

If the subnet ever reaches 10 or more Load, you must succeed on a Constitution saving throw at the end of your turn or take 4d10 force damage and have disadvantage on concentration checks until the end of your next turn.