The Faceless
The third member of the Noxian council in the new lore, "The Faceless" is a very ambiguous figure, but also very prominent in the story, do you think they're just a major plot point or will they become a champion in the future? It's mildly implied in the story that the character might be female; "The third figure—only ever referred to as “the Faceless”—was a mystery. This individual sat unmoving, bedecked from head to toe in a many-layered, voluminous robe. They wore a blank, staring, glossy-black mask, and even the eye-holes were obscured with dark mesh, giving away nothing as to their identity. Their hands, too, were concealed, hidden in sleeves of thick fabric. Alyssa thought she perceived a vaguely feminine aspect to the mask, but that might simply have been the way it happened to catch the light." But it doesn't truly give anything away. I'd be very interested to see what sort of gameplay the character would have if they actually did make them a champion, and how, if they wanted to, they would keep the character ambiguous.