Kayn’s passive is “War Scythe of the Dark” and determines whether he becomes Rhaast or the Shadow Assassin. Every time you deal damage to enemy champions, you collect stacks for the transformation. Melee fighters give you stacks for Rhaast and ranged fighters give you stacks for the Shadow Assassin. Whether an opponent counts as a melee or ranged fighter depends on whether their autoattacks count as melee or ranged attacks. As soon as Kayn has transformed, the passive gains new effects. Rhaast heals himself for a percentage of the damage his abilities inflict on your opponents. This allows him to counter-heal very strongly, especially when he hits multiple enemies. The Shadow Assassin’s abilities, on the other hand, deal additional magic damage in the first 3 seconds of a fight. This only applies if Kayn has not been involved in combat for 8 seconds or has used his ultimate ability. This turns Kayn into a combo-based burst champion who can take out one (or, if heavily fused, several) opponents in a matter of seconds.

At level 1, you start with Kayn’s Q “Scythe Vortex”, as this is best suited to clearing your first camp. When the ability is activated, Kayn jumps in the selected direction and strikes, both of which deal area damage to enemies he hits. You can also use this ability to scale thin walls. Thanks to this terrain scaling and the area damage, your Q ensures that Kayn has a very fast clear speed in the jungle. When maximizing, you should therefore always put 3 points into Q at level 1, 4 and 5 first. If you want to play Rhaast, then maximize her first. After transforming to Rhaast, your Q deals damage depending on the maximum life of your opponents, making you very strong in battles against tanks and bruisers. As a Shadow Assassin, on the other hand, the Q has no additional effect and you only put the last two points into the Q at level 12 and 13 to maximize it second.

At level 2, you skill Kayn’s E “Shadow Step”, which allows him to move through terrain. This gives him additional movement speed and heals him. If he is hit by a CC within the terrain or stays outside the terrain for longer than 1.5 seconds, this ability ends prematurely. As a Shadow Assassin, Kayn also benefits from a doubling of additional movement speed, gains immunity to slows during E and the cooldown of the ability is only 8 seconds instead of 21. As additional ability points only increase the duration of the E, both Rhaast and the Shadow Assassin are the last to maximize it.

At level 3, you complete your basic skill set with the W “Blade Strike”. Kayn deals damage in a line and slows his targets. As a Shadow Assassin, Kayn can also move further during the W animation and the ability has a longer range. These additional advantages are the reason why, as a Shadow Assassin, you only put 3 points into the Q for the jungle clear and then maximize the W first. Rhaast, on the other hand, throws enemies hit into the air for an additional second, which is also a strong bonus effect. However, the additional damage on the Q is more important for Rhaast, which is why he maximizes the W second.

You unlock your ultimate ability “Sinister Visitation” as usual at level 6 and also level it at levels 11 and 16. The passive of this ability ensures that enemies hit by Kayn’s abilities are marked for 3.15 seconds. The ult can only be cast on marked enemies. When activated, Kayn hides in the body of the selected enemy and bursts out of it after 2.5 seconds or when reactivated, dealing massive damage. As a Shadow Assassin, Kayn has an increased ult range, can continue to dash when he breaks out and resets the cooldown of his passives. With Rhaast, on the other hand, the damage dealt by the ult depends on the opponent’s maximum health and also heals Rhaast for a portion of it.

Your standard combo for maximum burst damage looks like this, regardless of your form: E->W->Q->AA->R. As a Shadow Assassin, however, you can perform it faster as you do not stand still for your W.