The New Champion might be Targonian
Looking at the in-game PBE teaser, I thought that the new champion seems to be Targonian based on the visuals of the spell(?), so I did some quick mock-ups of a black-and-white version of both it and
's VFX, which is supposed to originate from Mt. Targon.
Both of them are characterised by circular patterns & the planet-ish motifs (also seen in other Targonian champions such as Taric), and the new champ's spell seems to also have sparkly stars and other such lights. imo this is a clear indicator that the new champion is from Targon, but of course, I could be wrong :D
Great theory