Keleseth

Prince Keleseth was a member of the San'layn who served as the ruler of the southeastern reaches of Northrend — specifically as Scourge overlord of Howling Fjord — and as a representative to the Vrykul.

=Wrath of the Lich King=

Keleseth claimed to have traveled across the world and made several interesting discoveries, such as the fact that with the proper amount of "encouragement" one can extract all the truths that a man dares hide.

In the Scarlet Enclave, Keleseth first appeared in Acherus: The Ebon Hold on the second floor. Later, his brother, Prince Valanar, instructed fledgling death knights to seek Keleseth out at the Crypt of Remembrance. Keleseth instructed the death knight to assassinate Quimby, mayor of New Avalon, and retrieve his town registry. He then ordered the death knight to use torture tools to extract information about the so-called "Crimson Dawn" from members of the Scarlet Crusade. Finally, he directed the death knight to report to Orbaz Bloodbane at the Scarlet Tavern.

In a vision in the Grizzly Hills, Keleseth was seen resurrecting Archmage Arugal alongside Valanar, Theraldis, and Atherann.

The Lich King deployed Keleseth to Utgarde Keep in hopes of harnessing the vrykul's potential for destruction. Upon arriving, the ambassador found a people who were more than eager to assist the Scourge, and the keep proved to be an excellent staging point for terrorizing the Howling Fjord. Keleseth acted as the Lich King's eyes and ears in the Howling Fjord, and his primary residence was Utgarde, where he assisted Ingvar the Plunderer in organizing raids on the surrounding territory.

After the Forsaken's victory over the Alliance's North Fleet in the Howling Fjord, Keleseth appeared at Vengeance Landing with four Dragonflayer vrykul to taunt High Executor Anselm and invite the Forsaken to rejoin the Scourge. Anselm ordered his archers to fire at Keleseth, but the blood prince teleported behind the vrykul so that the arrows killed them instead of him. He then used his magic to drain the souls of Anselm's troops before vanishing. Anselm proceeded to send adventurers to kill Keleseth inside Utgarde Keep. During the assault on Utgarde, Keleseth was slain by the invading heroes.

Icecrown Citadel
Keleseth, along with his brother Valanar and Prince Taldaram from Ahn'kahet, were later raised into undeath yet again by the Lich King to form the Blood Prince Council. Their duty was to avenge themselves on the heroes that slew them and to protect Blood-Queen Lana'thel, the blood-queen of the San'layn. This new position proved to have the same outcome as Keleseth's previous one, and the blood princes were defeated once again.

See WoWPedia