Rohen Tahir, for a long time only known as "The Dark One", is the main antagonist of "Spellforce: The Order of Dawn" and an enemy in "Spellforce: Shadow of the Phoenix". He was the only Circle Mage to survive the convocation. Despite his villainous acts in his youth, he later saw his mistakes and tried to make amends as good as possible.
Although of young age, Rohen was one of the most powerful circle mages. As every one of them, he wanted to control the power of the Allfire and planned a ritual during the convokation. But as whe was about to start the ritual, an old man entered his tower and told him that the convokation would destroy him. What Rohen did not know, was that the old man was an aged Rohen, trying to warn his younger self from the evil power of the convocation. Blinded by his arrogance, Rohen attacked his older self and they fought. During the fight, the convocation erupted. Rohen did not die because his duel prevented him from partaking in the ritual. The power of the convocation killed every other Circle Mage and destroyed big parts of the world.
Both Rohens survived. Now known as The Dark One, the younger one deviced a new plan: using the Godstones to open the Time Portal and travel back through time to win the wars he fought against the other members of the circle and to gain the power of the convocation. He went to the city of Whisper and stole the secrets of the Iron Ones from the grave of his old friend Hokan Ashir. With this newfound army, he invaded the Icegate Marshes. He also gained control over the mercenary group called the Black Fist, using them to scavange through the realms of men and elves.
In the meantime, the older Rohen had gathered supporters and founded the Order of Dawn. Feeling guilty about what the Circle had done to the world, he used his power to create Portals between the last remaining inhabited Isles. He made no difference between the light and dark races, as that was the original intention of the Circle: bringing balance. He also summoned a Runewarrior
When he was told that the Iron Ones were sighted in the Icegate Marshes he recognized the signs. He immediately travelled to the Marshes, not knowing that this was a trap laid by the Dark One. When the Rune Warrior found out, he followed the old Rohen to the Marshes, but was only able to witness the Dark One striking Rohen down. The Dark One told the Runewarrior, that he should tell the Order that Rohen, their leader, had died.
When the remaining forces of the Order of Dawn invaded the Icegate Marshes to fight the Iron Ones, their leader Satarius was captured. The Runewarrior was able to locate him, but when he tried to open the chains, he was frozen by a protective spell. The Dark One appeared, killed Satarius and took the phoenix stone and a book from old Rohen about the convocation from the Runewarrior. With the power of the stone, he had everything he needed to open the Time Portal, making his search for the godstones unnecessary. He thanked the Runewarrior and ordered his Iron Blades to kill him.
He managed to open the Portal but was confronted by the Runewarrior. As the Dark One was not wearing his hood, the Runewarrior recognized him as a younger Version of the Rohen he knew, Rohen, not knowing what the Runewarrior was talking about, dismissed his words as unimportant and entered the Portal to change the past. When he arrived in the past, he read the book about the convocation and realised that he was a fool and had killed his older self. Trying to stop that from happening, he (now aged) entered the tower of the younger Rohen, trying to explain the situation but was attacked by his younger self. When this failed, he founded the Order, summomned a Runewarrior and headed to the Icegate Marshes, waiting for his younger self to kill him.
Shadow of the Phoenix
In "Shadow of the Phoenix" Rohen and all the other Circle Mages get revived by Hokan Ashir, using the Blood of Ereon. He is sent to command troops ath the battlement that bars the way to Kathay. When the Runewarrior stroms the fortress, he has to face Rohen, who rides an undead raptor. After his defeat, Rohens spirit is able to warn the Runewarrior and the troops of the Order, that Hokan has the whole Circle under his control and that they gather strength with each passing day. With his last words he tells them to free the Phoenix and to save Darius, the human form of Ereon.
Due to his death in his fortress, he is not present when the Runewarrior fights the Circle Mages and Hokan.