"Out of desperation, our enemies have activated the ruins' security system, powered by two energy pylons. Major Tull will explain."
"As soon as the system reaches its full charge, it will open a portal outside our camp. From what we've deciphered, that means disaster."
―An Imperial commander and Tull[src]

Tull was a major of the Imperial Military during the Galactic War between the Galactic Republic and the Sith Empire. Tull was knowledgeable as to the workings of Gree hypergates, and was called in during the conflict on Seline.