Haven't they done it already?
Yes I know people didn't like what came out. Is that why you're going there again? (Just to know) From what I know it was some other guy who was rushed to do it or something. Clear me out
The whole reason is likely because everything went wrong with the release, so they're fixing what's broken. Not sure if there'll be any extra story or if it'll be just filling in the currently existing blanks, but as seen with Kalista; they'll put out the new bio style and have the short stories they wanted to release as a part of that.
They also covering other Shurima champs like amumu and Rek'sai
next champ is from bilgewater
Not necessarily champions, but lore
