Jhin: The Deadeye of FATE?
Changed it Ignored it Denied it Ran from it
(In Order of Release)
Each of the teased champions' fate may not have been realized, and so Jhin removes what they hide behind and shows what they are missing (and kills them in the process)

So, as we know, Zed trained under Shen's father, and Shen is the Eye of Twilight. A saying goes "And as night/TWILIGHT falls on this mans life....." He's dead, right? Shot in the Eye. He could very well, by this theory, be shown that he was meant to be the Eye of Twilight, not Shen. But his impatience gave the position to him, leafing to the Master's death and so forth.
He hid behind his power, and he accidentally changed his fate from being the Eye of Twilight to The Master of Shadows.

She is missing her voice, and doesn't remember her real parents. Not even ONCE did her lore mention looking for a way to get it back. She may have, in truth had amazing powers tied to her voice, and the instrument was only compensation.
She hid behind her talent and ignored her fate of her voice.(Bad english, sorry)

His fate is to be with is Katarina (Based on unofficial but common knowledge). But his position and country won't allow it.
Pretty straight forward already. He hid behind his position and duty, and denied his fate of being with Katarina.

She is the hardest to see the fate that isn't (officially) there. Her fate, I believe was her criminal life, and how she could have helped THEM see the error of their ways, without excessive force. You know, helped Ajuna live, be a true friend of Ekko's, that sort of thing. But she fears she can not control herself.
She hid behind her powerful gauntlets, running from her fate to help the street kids and other lost souls.
- Jhin removed Zed's power and showed him his fate he changed
- Jhin removed Sona's gift (the instrument) and showed he the fate she has ignored for her entire life
- Jhin removed Garen's armor and position and revealed his true feelings and - ah, "powerful sword arm"
- Jhin removed Vi's gauntlets and revealed her frail, unsure and insecure self, because she actually KNOWS that she may have made the wrong choice.
Anyway, this is just my theory, please comment on whatever.