The Darkin Scythe
Kayn wields an ancient weapon and fights Rhaast, the darkin within it, for control. Either the Darkin will triumph, or Kayn will master Rhaast and become the Shadow Assassin.
Darkin: Heal for a percentage of spell damage dealt to champions.
Shadow Assassin: For the first few seconds in combat with enemy champions, deal bonus damage.
Kayn dashes, then slashes. Both deal damage.
Kayn damages and slows targets in a line.
Kayn can walk through terrain.
Kayn hides in an enemy's body, dealing massive damage when he bursts out.