Jhin's lore, specifically his childhood & his method of killing

I have no idea where I heard (read) this from, but I vaguely remember that Jhin's father used to run a martial arts dojo, and his father's dojo started failing because of Wuju dojos throughout Ionia. Additionally, I remember that Jhin used to use blades instead of guns before being employed by Ionian lords as an assassin.

Does anyone know where this information might have come from? Can anyone confirm if this is true or not? I've been trying to do a roundup of lore and have stuck on Jhin.