How strong is Kayn lorewise?

Ok , so we know that the Darkin are extremely powerful beings, it literally took an alliance between humans and vastaya to try and imprison them, which implies they couldn't kill them outright.

So if Kayn can use shadow magic in order to kill a darkin ( provided that Shadow Assassin Kayn is somewhat canon ) then it's safe to say he's actually pretty impressive for an ordinary human.

He can also seemingly resist Rhaast's corruption and doesn't really look like it's taking a huge toll on him.

The closest thing we can compare him to is Varus who took over two people and they have to work together in order to keep him in check.

We can argue that maybe Varus is simply a stronger Darkin than Rhaast and therefore he's harder to control, but that is unlikely given that Rhaast was second in command, with only Aatrox being stronger than him.

I really hope once we get the Aatrox rework we will also get some new lore about the Darkin race and possibly a story about Kayn.

Until then it's pretty clear he is a rather unique individual ( one of his quotes is literally "There is no one like me" ) and I think Riot did a pretty good job when designing him and his lore.

What do you guys think about this ?