I was hoping to do some encounter deck spring cleaning with this card re-used via The Painted World until I realized Sefina Rousseau is only a humble Artist.
I am sure there is more potential with this card than just giving the fight head and hitting really hard, but it feels like its greatest strength is its greatest "weakness", kind of: You cannot really recur it with Prescient or other means, because it doesn't go into your discard pile if you pin an enemy to the board.
BUT what if you put this under Dayana Esperence? Contrary to other cards her text prevents the attached card from being discarded without it being a dedicated replacement effect (lacks the word "instead"). The part of her ability that sounds like reminder text ("it remains attached") is the one that would actually prevent Blood of K'n-yan from staying in the victory display. This seems very ambiguous and more like an oversight, but strictly as written I would argue that the interaction works.