Rogen was an old and blind magician with the ability to see into the future.
He was driven from his village years earlier, because he foretold the death of the town miller and was blamed for it. He was branded a warlock
He was living in an abandoned hunter's lodge in the forest when he found Gamina, still a baby, abandoned in the woods. He worried about what will happen to Gamina when he dies.
When they heard words of Stardock, they journeyed for six months to reach the place, where they can live as source of knowledge, not a source of fear.
Dominic explained that Rogen's sight as capable of seeing probabilities. It also seems to require a great deal of the user's energies, leaving Rogen exhausted.
Rogen was asked to look into the future for the Kingdom of the Isles. When he did, he was harmed by the Darkness. He fully recovered from his ordeal, acting as grandfather to Gamina and William. He died three months prior to the battle at Sethanon.