The Genii
The Genii appeared on first contact to be a peaceful and fairly primitive race. However on closer inspection the Genii have been conserving knowledge and technology below ground away from the culling of the Wraith. They hope to be able to destroy the Wraith once they have gained sufficient weapons technology. They try and persuade the Atlantis team to part with an A-Bomb, but as the Atlantis team find out - the Genii dont take no for an answer.