Riot, your lore has a plothole
((Solved. Apparently I've been grinding too hard for too long and completely missed years of entire lore reworks. "Retcons" I quiver at the thought. It's still a beautiful game though. I'll leave the thread open in case anyone is interested in Kayn, Darkins, or the intricacies of Runeterra and the Summoners.))
Now hear me out, I hecking love this game, the lore especially, it's beautiful and cinematic. And I have a suggestion at the end, it isn't merely hatemail.
The Summoners Rift is a field of battle where we, the Summoners - some nondescript authorities of Runeterra - summon the Champion, from their own plane of existence, into our world, so that they may be our channels of power to settle our conflicts without any actual bloodshed. (Given that we're 'above these mortal beings' and all) It's absolutely beautiful. We're practically gods, and they are our champions - To be summoned to our plane at our beck and call, either for their own sense of purpose, or as a sort of tax, imposed on them for the power they wield.
The plothole? Kayn. Wh-what? He picks up his scythe, a Darkin weapon, and is called once, forever to our field of battle?
For those of you who don't know lets explain a Darkin. A spirit trapped within a weapon of some kind, able to enter a symbiotic relationship with a mortal through which one of them will eventually perish. "the Darkin can parasitically dominate their wielder, thereby annihilating the wielder's personality while in turn freely affirming their agency; similarly, the wielder can extirpate the Darkin's persona to gain full access to the weapon's power. In both cases, the dominated other is described as "dying"."
Kayn can not come to some conclusion with his weapon repeatedly. That is the definition of a Darkin. One of them dies when the other takes full control. My suggestion? An event! His current lore ends with him finding the scythe. Do something between Kayn and a time mage (Like Ekko or Zilean). Maybe, after the first time he was summoned, through personal interest or accidental mayhem, he and his weapon are thrust back in time before the decision has been made, and he sets the weapon down for thoughtful contemplation. Only to finally find some new purpose in this personal conquest of inner understanding, knowing himself and the weapon before him. And so, he decides after being reset to original Kayn, he wants to do it all again, and again, if only for the skills he might attain as a master assassin. (And implicitly sets up some kind of deal with the time traveler [or repeatedly enters an accident, if it was that! It's not my lore!])
Thanks for reading and I hope y'all see what I'm saying. This is an amazing story and Kayn is the only non-living character in the world.