OK i was googling some old lore about Youkuda and i knew every land was dominated by elves before the rise of man and all that jazz. And i found something talking briefly about Left Hand elves from Youkuda and how they were probably wiped out by Redguards. DO yall know of any information regarding these Mer?

*Yokuda

There's nothing much about them other than they built Orichalc Tower before the destruction of the continent. Theres practically nothing surviving of their legacy.

Their empire was reputably http://imperial-library.info/content/lord-vivecs-sword-meeting-cyrus-restless the size of Tiber Septim's. Being that the speaker has a reason to brag, lives 3000 years after the fact, and has never actually been to Tamriel, the accuracy of the accuracy of the statement is questionable.

they could be called left handed, as in they were sinister mer. Nothing really to support this, other than sinister = on the left, and threatening evil/harm/etc

Ra'ga culture's emphasis on swordfighting might cause them to view a left-handed fighter as unusual, dangerous, or otherwise noteworthy.

Or, since the techniques of the Ansei as revealed to Cyrus through memory stones teach left-handed techniques, it could be a term of praise.