So, I have an Idea about Jhin's (Deadeye) origins...
In the new trailers for the new champion, I've noticed that on Jhin's gun, there's the numeral for four: IIII. I realize that that's usually not Roman Numeral, but it does apply, in some cases.
I know that there's a particular old gang in Zaun,
,
,
, that uses Roman Numerals in their names, or on their items. Ekko's being on his weapon, XII.
So, I thought of it as maybe just an odd coincidence, but I was curious, none the less. So, I thought I'd check out Ekko's "Seconds" video, and at the time of 1:05 in the video, you can see on the wall behind Ekko, that there is a face there that somewhat resembles the mask Jhin has on in the traile
I've noticed Jhin to take in his killings as "Art". Maybe He was the one who drew the art on the wall?
Again, this is just speculation, and if anyone has any other ideas, or ways to disprove this theory, feel free to comment!