Karthus

Innate: Upon taking fatal damage, Karthus enters a zombie state for 7 seconds, during which he can cast his abilities at no cost. If Defile has been learned, it will remain toggled on for Death Defied's entire duration. Requiem becomes disabled after 4 seconds of the duration have elapsed.

While under this state, Karthus becomes untargetable and immune to crowd control as well as prevents all incoming damage, but is also rendered unable to move, declare basic attacks, use summoner spells, and activate items.

Active: Karthus conjures a blast at the target location that detonates after 0.528 seconds − 0.759 seconds, granting sight of the area and dealing magic damage to all enemies within, doubled when only one target is struck.

Active: Karthus erects a wall of pain at the target location perpendicular to his facing that lasts 5 seconds, granting sight around its pillars and center.

Enemies that touch the wall are inflicted with 25% magic resistance reduction and become slowed for 5 seconds, decaying over the duration. This can affect enemies only once per cast.

Passive: Karthus restores mana whenever he kills an enemy.

Toggle: Karthus surrounds himself in a necrotic aura that deals magic damage every 0.25 seconds to all nearby enemies.

Toggling Defile off triggers a final tick of damage. Defile is toggled off automatically if Karthus becomes unable to pay its mana cost.

Active: Karthus channels for 3 seconds, then deals magic damage to all targetable enemy champions upon completion.