Deadeye/Jhin and what they stand for.
After this final teaser I've come to a pretty solid conclusion.
In this case, Vi loses her gauntlets, a major characteristic trait for her. Yet there's one thing. The gauntlets also stopped her ambition. Vi wants peace, her being an officer and all. Yet she uses violence (the gauntlets) to enforce this peace, thus counteracting her wish.
Sona is a musician, known for playing the Etwahl and all that. Yet, she's a mute, due to an unknown curse that hinders her. In her teaser she was shot in the throat, which is where the vocal chords are.
Garen is a warrior for Demacia, a straight-justice kingdom that doesn't take mercy, only battle and justification. Garen's selection quote is: 'My heart, always for Demacia'. Yet, in the teaser...he's shot in the chest, presumably in the heart as well.
And finally: Zed. Zed was blinded or corrupted by the shadows once he opened the chest that contained them. In his teaser...he was shot through the eye, with a blue light being visible. Perhaps this shot had purified his mind?
It's not plausible to say that these champions are in fact dead. Considering the icons you see make them look like...they're sleeping, or in a comatose state. If anything they look more at peace than any other time. Could it be this person, Deadeye, Jhin, whatever you want to call them, is freeing them of the restraints that keep them from their dreams and ambitions?
Feel free to discuss what you think these teasers could possibly mean, this is just my take on it. Everyone has a different view.