In that vid you see yi having flash backs of fighting an elder like person his r shows him going at sonic speed which could resamble a wind technique and his q, alpha strike moves fast "like the wind" the reason yasuo never has a quote to this is because yasuo has NEVER heard of wuju thats why yasuo still hasnt found the elders killer please 1+ this i want everyone to know after my hours of research i have found it out :D.
vs 
Yasuo killed the elder while he was drunk. That is why he doesn't remember.
I thought it was riven, but okay.
The assumpion of high speed = wind magic is where things fall off. Also we know that Yi memories are not his and might be instead Yasuo memories (same file name).
Uhm you did link the video of the login screen that only shows Yi killing some robots.
Also the person yi fights in his memories doesn't look like an elder at all,more like some bloodthirsty warlord/general. Not to mention that the whole thing behind Project Yi is that he got fake memories implanted into him,which have been hinted to be actually Yasuos memories.
