Colonel Sean Grieves had commanded one of the rogue off-world NID teams under Colonel Maybourne. On one of his missions he had stolen a powerful beam weapon from P3Y-294, and used the device on his pursuers, killing three, and irreparably damaging relations with the planet's government. On Latona, he had tried to steal the technology of the Sentinel, and he had killed the Caretaker, rendering the planet defenseless. When Maybourne's off-world operation was shut down, Grieves was convicted of high treason and sentenced to death row, however he was offered a commuted sentence if he agreed to return to Latona to assist in repairing the damage to the Sentinel. On the return mission, Latona came under attack by the Goa'uld Svarog, and Grieves gave his life to save the planet when he activated the Sentinel in the Caretaker's place, and vanished.
Portrayed by: Frank Cassini
Episode Reference: The Sentinel