Tibianus III wanted to build the grandest city ever. In order to accomplish this, he sent his workers and his elite army unit, the Red Legion, north to build him his city. The Red Legion were cruel to the workers and many believed they didn't even try to protect the workers due to the fact many Orc raids happened. The workers soon began to protest and rebel against the harsh conditions put on by the Red Legion. So the general of the Red Legion began to lock up any that rebeled in Elvenbane that was recently constructed along with Carlin. A group of these prisoners where one of the king's sister's friends. As her scouts told her of the harsh conditions in the castle she made plan to destroy the Red Legion, ending their reign of cruelty of the workers.
As her plan unfolded she gathered all the druids and hunters loyal to her, she made them dress up as Orcs and every night they would attack Elvenbane. Finaly the general of the Red Legion got tired of it and they marched out during the night to destroy the Orcs. The real Orcs that were there were not prepared for an attack and the Red Legion desecrated them with little of their own casualities. It is rumured the the Orc Shaman cursed the Red Legion and the remaning Orcs scattered acrossed Tibia seeking out allies among the Minotaurs, Trolls, Cyclops. With their forces bolstered they begin to lay siege to the castle. Knowing that the prisons lead underground they begin to dig a tunnel. During this time the workers were being forced into their rooms by the guards. When they breached the underground walls chaos insewed as the desperate workers tried to get away, but were trapped between the orc alliance and the guards trying to get down to fight.
The King's sister hearing word of the siege quickly rushed with her own forces in hope of saving the workers but, by the time they got there, it was too late and the orc alliance began to attack her forces, forcing her to withdraw back to Carlin. After the siege she could not allow such a powerful force so close to Carlin. So she deprised the same trick as she done with the Red Legion where she started turning the Orcs allies against each other. By doing this, she saved Carlin...
As the orcs and the other races of the alliance went their separate ways there is still a stern occupation of the castle with all the races. Many other creatures have started joining them as well including the Elves who come to study the ancient knowldege that was capture from the Red Legion. Many spells and strange powers surge from the main tower do to their eradic experiments.
Elvenbane is an island just west of Ab'Dendriel (here). It is only accessible from an underground cave with it's entrance located (here). The Elvenbane Quest can be found here.
Also, note that the passages in the castle of Elvenbane are so narrow that only one person can walk through at a time. Often people will purposely stay in your way if a lured Orc Berserker or Minotaur Guard comes your way. So be careful!