[Speculation] The recent teasers reference the Wise Monkeys?

We can see already that Zed has been shot in the eye, and Sona has been shot in the throat. I suspect very strongly, based on the face of Garen in the leaked picture, that he will have been shot in the ear. And since there's a fourth, Vi, especially since she has MASSIVE hands, I suspect she will be shot in the hand or chest.

If the above holds, this is very reminiscent of Mizaru, Kikazaru, Iwazaru (the original 3) and Shizaru (added later), the four wise monkeys. They collectively represent:

See no evil, from Zed's eye (Mizaru is a pun saying Do not see, but 'zaru' is also a modification of 'saru', meaning monkey) Hear no evil, from Garen's ear (Kikazaru) Speak no evil, from Sona's throat (Iwazaru) Do no evil, from Vi's hand/chest (Shizaru; I'm leaving the option of the chest because 'doing evil' can come from a corrupt heart)

Based on this...perhaps the champion being teased is a simian with a strong sense of justice? I find that a little similar to Wukong... but it's far enough away that I think it could work, if done well. If not an actual simian, at least someone with a very traditional, 'maintaining the old ways of good' kind of personality? Since the proverb is quite old.

Edit1: As @JettStreams points out somewhere in the comments, it could easily be Vi who does not hear, and Garen who does not do. In which case the cracks on Garen's face might not be his ear, but just his head in general.

If we think about it, Zed already cannot "see evil" because in his eyes, there is no evil in his doings, there is only the pursuit of his goal (power, knowledge of the shadows..)

Sona already cannot "speak evil", not only because she's mute, but because what sounds she DOES make (via her instrument) appear, to her, to carry purpose and benefit (healing, raising morale...striking down foes)

Vi already cannot "hear evil" because, while she certainly acts on her own internal rhythm, she still acts in the interest of Piltover (albeit in a roundabout, reckless manner), and Ekko at the least (and probably others that slip my mind) has faced the internal dark-side of Piltovian (Piltovan? Piltovese? Piltovish?) society. She hears no evil in the orders she's given, even though she still usually doesn't follow them to a T.

and Garen cannot "do evil" because, according to the Demacian courts and perhaps even in his own mind, Demacia is a just, fair nation that is the epitome of righteousness. Everything he does in the name of Demacia is, by Demacia's definition, justice, not evil.

Edit2: I also just realized that next year is the Year of the Monkey. So there's that.