Officer in the Genii military, on the Genii homeworld. Prenum welcomed a dialogue between his people and Atlantis when Elizabeth Weir contacted them for help. But on the other side she was bound, blindfolded, and taken to a secluded compound where Prenum interrogated her, hoping to use her as a bargaining chip for more of Earth's C4 explosives.
Despite captivity, Weir pushed her case, asking for two Genii nuclear devices to defend Atlantis from the Wraith. This way, the Genii could see if their weapons worked -- at no risk to themselves. Though Prenum argued that the threat of the Wraith had recently come and gone, he could not deny that the operation of the technology would probably become important again in the future.
Prenum returned Weir to Atlantis and sent two officers to deliver twin nuclear devices (though incomplete) to Atlantis base.
The Siege, Part 2 - Weir bargains with Prenum for a demonstration of Genii nuclear technology at no risk to his people.