Blackklaw was the ebon gryphon mount of Daerion of the Stormwind Assassin's Guild, who tried to kill Lo'Gosh. Blackklaw was killed by Valeera Sanguinar.
This article or section includes speculation, observations or opinions possibly supported by lore or by Blizzard officials. It should not be taken as representing official lore.
It's possible that his name is a typo and was meant to be Blackclaw.