Tamiel is the leader of the evil church of the Sydonai on Roak that worships Asmodeus and he plots to destroy the world. He appears to be a power crazed, and somewhat psychotic, Human, but is in fact a Grigori. He is fought by the SRF party in the Inner Sanctum of the Purgatorium.
Tamiel is first met at Tropp, attempting to spread the cult of the Archfiend Asmodeus, who will save all mankind with destruction and guide them to a new world of peace. This is an adaptation of the goal of the Grigori and the Missing Procedure to the people and culture of Roak, which shows Tamiel has the same thought pattern as all the other Grigori.
When the party have made their way through the Purgatorium they reach a large chamber in which Tamiel is worshipping Asmodeus. He reveals his plan to cleanse the world through its destruction. After much debate Edge's symbol on his hand begins to glow and the whole party feels ready for battle. Tamiel does not transform into a creature but is accompanied by Sydonaist henchmen.
- Main article: Tamiel (Boss)
He appears has a quite tall man with a staff for using Symbology. His attacks mainly consist of aerial symbology or swipes of his staff in close quarter combat. He is constantly surrounded by henchmen and revives them if the party kills them all.
Defeating Tamiel grants the player the "Trounced Tamiel" Achievement/Trophy.
- The leader of the Church of Sydonai, the cult that has thrown all of Astral into chaos. Tamiel fights to eliminate all who oppose the resurrection of Asmodeus. In addition to symbology, he also has a range of special attacks granted to him by the powers of Asmodeus himself. If he uses too much of his power, he goes out of control, as if the power itself has taken over his body. He looks human, but the truth is far more complicated...
Tamiel is one of the Grigori, a group of fallen angels from the Book of Enoch. His name means "perfection of God". In mythology, he taught mankind how to hurt, abort and cause pain.
- Tamiel is one of the few antagonists in the series to acknowledge a major antagonist from another Star Ocean game (Asmodeus). The only other antagonist to do so to date is Mother Edifice.