firstly love the way you drawn your concept, aquatic tank I presume
but.. I cant think of a lore that would make him fit in the LOL, they mostly go for thematics, and character's lore that interacts with each other, and although it somewhat related to fizz, the relationship just stops there, or maybe him being a knight goes to demacia, but demacia has an eastern~ish feel to it, unlike western king, knights. also I don't think they wanna make somethin that resembles another games champion, "SIR BENZINGTON".
also, do you have any higher res of this image? would love to make it a background :3