Using only information inquired from Lore, the killer of Yasuo's master is 100% Unidentifiable.
And before people pull the "Riven" Card, No where stated in Rivens lore does it claim she can use any wind techniques.
However, i'm gonna leave it to you guys to try to identify it.
using only lore, that is.
You say we should count just the lore,but the problem is that in 90% of the champion lores,they do not talk about their individual abilities.
Riven has an ult called Wind Slash and ingame even yasuo recognizes the similarities between that technique and his own wind technique. Add to the fact that Riven is pretty much the only noxian champ where its confirmed that she fought in the ionia invasion(Swain for example did not participate in that),means that she is the most likely subject that we have.
However that doesn't mean that she really did it.It wouldn't surprise me if Riven was just a red herring,or if riot later released other possible suspects.
Who says that someone with a wind technique killed him?
And before people pull the "Riven" Card, No where stated in Rivens lore does it claim she can use any wind techniques.
So... i guess that her "Wind Slash"
http://img2.wikia.nocookie.net/__cb20130929123219/leagueoflegends/images/6/6d/Wind_Slash.png
... is not a "wind" Technique.... right? It must be a slash of fire or something like that.
Seriously why does everyone think that Yasuos master got killed? It was an ionian ELDER not his master.
Unreleased Champ or Plot Cliffhanger.
