Dark Iron Ambassador

The Dark Iron Ambassador is a rare elite mob Dark Iron dwarf in Gnomeregan.

The ambassador was very likely the envoy between the gnomish traitor Sicco Thermaplugg and the foul Dark Iron clan, led by the Emperor Dagran Thaurissan.

Speculation
The Dark Iron Ambassador's purpose is never explained. The loss of Gnomeregan is the topic of in-universe conspiracy theories, with the involvement of the Dark Iron clan notable information.

The non-canon RPG says that Thermaplugg had opened up negotiations with the Dark Iron dwarves, allowing them the use of Gnomeregan's tunnels in exchange for a part of Ironforge to call his own.

It is possible, though unlikely, that Dark Irons had a deal with Thermaplugg to direct the troggs to Gnomeregan from their operations in Uldaman where the troggs originated.