Innate:Kayn wields an ancient, sentient weapon, that battles with him for control. Dealing damage against champions causes them to drops orbs that are automatically collected upon leaving combat (including after Kayn's own death), filling a bar above Kayn's portrait.
Once the bar is full he can choose to either be overwhelmed by Rhaast or expel him to become the Shadow Assassin, based on whether he has damaged more melee or ranged champions, respectively. Once primed, the other option becomes available after 4 minutes.
The transformation can only be performed by interacting with their portrait while on the summoning platform, permanently changing their abilities.
Shadow Assassin:Kayn's basic attacks and abilities deal 12% - 44% (based on level) of post-mitigation damage as bonusmagic damage, lasting for 3 seconds upon entering in combat with an enemy champion, refreshing after 8 seconds out of combat with them or by using Umbral Trespass.
Rhaast:Rhaast heals for 26% - 43% (based on level) of the post-mitigation damage that he deals with spells against enemy champions.
Active: After a short delay in which he can't perform any other actions, Kayn performs an upwards sweep with his scythe, dealing physical damage to all enemies in a line and slowing them by 60%, decaying over 1.5 seconds.
Shadow Assassin:Blade's Reach'srange is increased by 200, deals an additional 10% bonus AD damage and the slow decays over 2 seconds. Additionally, Kayn conjures a living shadow at the casting position to perform Blade's Reach in his stead, allowing Kayn to perform other actions.
Entering combat with a champion after the effect is enhanced reduces the remaining duration to 1.5 seconds. The effect also cannot remain active out of terrain for longer than 1.5 seconds.
Shadow Assassin: Casting Shadow Step removes slows and makes Kayn immune to them for the duration. Additionally, entering terrain will increase the bonus movement speed to 70% for the remaining duration.
PENDING FOR TESTKayn's definition of "in-combat". The spotlight shows him gaining the empowered duration even after being hit by a non-damaging, which could either mean non-damaging effects don't classify him as being in-combat or that the timer begins after activation.
Effects such as Vayne'sCondemn and Poppy'sHeroic Charge apply an immobilizing effect and so interrupt Shadow Step, meaning as Kayn's opponent you do not have to worry about pushing him to safety.
However, enemies will be notified if nearby terrain is infested if Kayn is within 1000 units - with an indicator being placed on the terrain with a direct line between Kayn and the enemy champion. Slightly less than standard sight radius, but more than the Camouflage detection radius.
Kayn can move up to 550 units beyond the outer-edge of the battlefield.
Rhaast:Umbral Trespass damage is modified to deal 10% (+ 13% per 100 bonus AD) of target's maximum health physical damage, and heals him for「 70% of the pre-mitigation damage 」「 7% (+ 9% per 100 bonus AD) of target's maximum health 」.