Demon Gate



The Demon Gate was a demonic portal found in midst of the Blackrock clan village of Blackrock Camp.

The Demon Gate was guarded by the orcs of the Blackrock Clan, but they proved no match to the Undead Scourge led by the Death knight Arthas and the Lich Kel'Thuzad. Kel'thuzad then used the gate to communicate with one of the lords of the Burning Legion - the dreaded Archimonde. It was here that Archimonde instructed the Scourge to attack Dalaran and claim the Last Spellbook of Medivh in order to summon him into Azeroth.

Notice how it is identical to the Dark Portal as it appeared in WC3, seen in the interlude The Last Guardian.

The other portal
In the Horde Player's Guide, it is stated that Kilrogg Deadeye and his Bleeding Hollow Clan - after the Horde had been defeated by the humans at the end of the Second War - escaped back to Draenor through another portal summoned by him and his warriors. Beyond the Dark Portal tells however that Kilrogg escaped back through the Dark Portal, which had been reopened by Teron Gorefiend after Khadgar somewhat destroyed it to stop the orcs (although he discovered that he couldn't completely destroy the dimensional rift it consisted of). If Kilrogg really did use another portal, it might've been the same as the Demon Gate.