Is Rhaast a clue for the Darkin lore as a whole?

I know that everyone right now is raving over the knew champion, Kayn (and understandably so, I mean the dude's a frickin' badass!), but I for one am more fascinated with the scythe that he wields, A.K.A. Rhaast. According to Kayn's lore Rhaast is a living Darkin weapon, similar to Aatrox's sword, and what this scythe does is it seeks out a worthy host to attach itself to, while destroying any unworthy hosts who attempt to wield it. After reading this I took into account Aatrox's old lore, which states that Aatrox is one of five remaining members of an ancient race known as the Darkin, but has since been removed. I don't know if Aatrox's old lore is still canonical or not, but this leaves one of two possibilities: either Aatrox and the other four Darkins created parasitic Darkin weaponry and spread them across Runeterra in hopes of saving their dying race, OR the Darkin are the weapons themselves, meaning that Aatrox could of at some point just been an ordinary swordsman until he found the sword that he currently weilds, thus turning him into the monstrosity that he is today. I'm just curious to see what you guys have to say about my theory, because it's pretty clear that the Darkin, while mysterious, are very important in terms of lore. After all, for those of you who don't know, Summoner's Rift was the result of Aatrox intervening during a battle that happened long ago, and this battle just so happened to occurred on what would later be deemed Summoner's Rift. Coincidence? I think not ;)