- He is the seventh dark-themed Ionian-affiliated champion (albeit Noxian-born), after , , , , & ; as well as the second-known member from the Order of Shadow.
- He is one of fifteen champions whose abilities don't scale with ability power, like , , , , , , , , , , , , , and
- His surname Kayn likely derives from :
- His stint as a child-soldier references the real-world
- Not all Noxian commanders condone their colleagues' callousness, though they at least turn a blind eye.
- Kayn may be a possible reference to Ling Yao , a character from the anime Full Metal Alchemist Brotherhood . Both characters share similarities in that a superhuman entity reside in them which vies for control of their bodies (Rhaast a Darkin inside Kayn and Greed a Homunculus inside Ling Yao). Moreover, Kayn shares quite a lot of similarities in character design with Ling Yao.
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- His appearance pays homage to both Dante and Vergil, the twin protagonists of 's game series Devil May Cry, with Vergil's color scheme and Dante's casual & confident attitude that he can subdue any demonic weapon to his will.
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- He shares this theme with [ | , and [ | .
- The Shadow Assassin form seems to reference Slave Knight Gael from .