"The Viper" on its own is not known at all - "The Viper of Glades" is basically just what his eldest brother jokingly nicknamed him a few times, and Jordan dropped the "of Glades" part. If there are any kind of vipers or adders native to Rodoria, there should probably be at least two dozen Vipers running around to boot...
	His actual name (Sir Yanin Glade) is moderately known, especially in Etlon, where his family resides, to some extent in Seclyr, where he served for about year and a half, and to a smaller extent in Zerul City (the last in part courtesy of Lady Alaisi). Primarily known for combat prowess, secondarily just for being a Glade. The more specific speculations are endemic to people who actually know the particular members of the family, and have perhaps met him. 
	(There is at least one more thing Morgan would be immediately notice about him owing to him having been made a sniffer, but I'd probably PM it when Yanin actually shows up.)

	Hmm... Morgan was a blacksmith apprentice from eleven to turning eighteen, when he was made sniffer, then he was a sniffer for ... months, a year? before being turned into vampire, and now he's thirty, so might have spent a bit over a decade as a vampire. How far has he traveled as a vampire? ((Trying to figure out what the actual timeframes are for Morgan.))