Infuses a lone enemy unit with swirling, volatile energy, dealing damage over time. The damage is not applied if another enemy unit is near the target. Arc Warden: Slows the target's movement speed. Tempest Double: Movement speed slow is decreased, but damage is increased.

Arc Warden: Generates a circular distortion field of magnetic energy that grants bonus attack speed and protects allied heroes and buildings within it by evading attacks coming from outside the field. Tempest Double: Allies gain bonus attack range and deal bonus damage with their attacks. Duration is increased.

Arc Warden: Summons a Spark Wraith that slowly materializes and patrols a targeted area until an enemy comes within its range. Once a target has been found the wraith fuses with them, dealing magical damage and slowing the unit. Non-hero units receive 40% more damage. Tempest Double: Increased Wraith Speed and slow duration, decreased Activation Delay and Damage.

Briefly refocusing its fractured elements into a single form, the Arc Warden is able to create a perfect electrical duplication of itself. The duplicate can use all of Arc Warden's current items and special Tempest Double versions of his spells, except most consumables and items that drop on death. The duplicate has separate item and ability cooldowns. The Tempest Double gives bounty gold to enemies when killed. The Tempest Double loses its sense of self if he is too far away from Arc Warden and deals less attack damage.