The newest lore release that was the Malzahar story is full of information that can be gleaned if you look hard enough. Speculations abound that, after the chem baron support, the newest champion may be from the Rift, and will likely be female.
The story follows Mier. A Noxian refuge fleeing from Noxus as a deserter, after striking an officer. Fearing for his life he travels as far away as possible and ends up in Icathia.
There, he finds himself among cultists following their leader, Malzahar, and feeding humans and animals to an impossibly large pit in their midst, one which he describes as capable of swallowing an entire city.
After a meeting with Malzahar, and listening to his sermon, Mier alongside everyone else present, is swallowed by the expanding pit, followed by Malzahar's words:" She wants everything. And she will have it".
From these words, we can extrapolate that the creature, currently inhabiting Icathia, though it seems not for long if Mier's visions of the fall of Noxus at the hands of the voidlings are to be believed, is a mix between Rek'sai and Cho'Gath. An impossibly large creature, following the Void theme of devouring everything in its path, that is distinctly labeled as female and seems to be the object of worship. This would, lore-wise, rank her higher in the hierarchy of the Void, compared to other Void champions that have found their way to Runeterra by accident.
This would not be the first time RIot have teased a new champion through stories of champions connected to them, with examples such as Rell and Yone coming to mind, and with the Void having only one top lane champion, it is likely that this is where the newest champion will end up. However, there have been rumors about a new Void-themed jungle, so all that remains is to wait and see what Riot have in store.