Mordekaiser's basic attacks deal bonus magic damage on-hit equal to 40% of his ability power.

After 3 basic attacks or abilities against enemy champions and epic monsters, Mordekaiser gains Darkness Rise for 5 seconds, causing him to deal 5-15 0.3) (+1-5% of target's maximum health) magic damage (depending on level) per second to all nearby enemies and gain 3 / 6 / 9% bonus movement speed (at levels 1 / 6 / 11).

Further basic attacks and abilities against enemy champions and epic monsters refresh Darkness Rise's duration.