I think the font is fine. If you do decide to change it, though, I would maintain a very bold style so you retain a good bit of the image. One thing I would suggest is you consider going with the standard splash for Ahri as you did with the others; using a skin for her alone gives it a bit of an unbalanced design. When I first looked at it I thought maybe Ahri isn't a good choice for "A," but then I realized that it's probably that she has a skin there where the others don't.
Also, with that much going on in the fonts, be sure your background is super simple. Too much clutter is an eyesore and takes away from all the elements. I would suggest a light background choice too, because the "E" fades into the black and looks somewhat like an "F" because of the coloring in Ekko's splash.
Overall, I really, really like this. It's a great idea and it looks like you have a great way to pull it off.
EDIT: Just noticed the coloring in Diana's splash has the same effect on the "L" as the Ekko, so just reiterating my suggestion on the light background.