Darkscale Taskmaster

Darkscale Taskmaster is a naga located in Tomb of Sargeras. He assists Harjatan and controls several Razorjaw murlocs.

Speculation
Given the similarities of the names, he may have been intended to be a Tidescale naga who are actually present during the raid. Harjatan is commanded by Mistress Sassz'ine who is surrounded by the Tidescales.