Yes, someone wielding sword, bow or scythe is common in fantasy when it's independent. But they share theme. They are Darkins, quite obviously looking like judo-christian demons, the three Darkins just happen to wield these weapons. We have Garen who is the fantasy sword-wielder archetype, Ashe who is the fantasy bow-wielder archetype.
Also, I love how Kayn in your version is supposed to be inspired by death when the horseman of apocalypse that wields scythe in depictions is literally death, called Death and said to be accompanied by Hades. From this very fact I sense you are the fedora-type who just hates the idea that someone gets inspired by Biblical myths.
It's the same thing as If Riot released a wolf/dog-like champion from Freljord who represents doom, is connected to the end of the world by devouring and If someone pointed out it sounds like Fenrir you'd be like "I grow tired of people who are trying to apply Norse mythology everywhere". LOL.
Or If people would be pointing to Ascended being connected to certain Egyptian gods. "I grow tired of people who are trying to apply Egyptian mythology everywhere."