Karthus will still benefit from cooldown reduction during Death Defied's duration.
Death Defied will still trigger if Karthus is killed by the Nexus Obelisk.
RANGE:875 / 200
COST: 20 / 26 / 32 / 38 / 44 mana
Active:Karthus detonates the target area in the direction of the mouse cursor after a 0.5-second delay, dealing magic damage to all units within. This damage is doubled if the detonation hits only a single target.
Lay Waste grants a small instance of sight before detonation.
Lay Waste hitting a single target lists damage as a critical strike both in the damage text in game and in the post-game screen, where the damage from Karthus's most powerful Lay Waste will appear in the post-game's "Largest Critical Strike" section of the graphs.
Despite this, Lay Waste can not actually critically strike and, as such, does not scale with Critical Strike Damage even if it hits a single target. It also will not trigger Warlord's Bloodlust or Essence Reaver's mana regeneration.
Wall of Pain
COST: 100 mana
Active:Karthus creates a wall at the target location for 5 seconds that provides sight around it for the duration, slowing units who pass through it by an amount that is reduced after 1 second and that decays over 4 seconds and reducing their magic resistance by 15% for the duration.