Abilities
Kayn chooses between Darkin (heals from spell damage) or Shadow Assassin (bonus damage early in combat).
Kayn dashes and slashes, dealing damage in an area around him.
Kayn slashes in a line, damaging and slowing all enemies hit.
Kayn gains the ability to walk through terrain for a short duration.
Kayn possesses an enemy champion, then bursts out to deal damage.
Guide
Kayn excels at skirmishing and flanking in ARAM; adapt your form based on enemy team comp, using walls for mobility and your ultimate to outplay burst or CC.
Tips
In ARAM, Kayn can transform faster due to constant teamfights; prioritize hitting ranged champions for Shadow Assassin or melee for Rhaast.
Use your E to quickly traverse the map and dodge skill shots, but beware of CC that can knock you out of walls.
Build accordingly to your form: Shadow Assassin benefits from lethality and burst, while Rhaast needs bruiser items like Black Cleaver and Death's Dance.
Snowball is excellent on Kayn to engage or finish off low-health targets, especially for Rhaast's knock-up combo.
Save your ultimate for dodging key enemy abilities or waiting for cooldowns, not just for damage.
Combos
Shadow Assassin: W -> Q -> auto-attack -> R to finish or escape.
Rhaast: Snowball -> Q -> W -> auto-attacks -> R to heal and reposition.
General: E through wall -> W -> Q -> auto-attack -> R to dodge retaliation.