A race of humans in the Pegasus Galaxy who have used extreme measures to hide their technological advancements from the Wraith in order to eventually strike back with nuclear weapons. On the surface they appear to the outside observer as simple, Amish-equivalent farmers. Below, they are engaging in a massive military undertaking where they plan to have atomic weaponry completed in time to strike back during the next culling of their civilization.
Approximately one thousand years ago the Genii were once the focal point of a great multi-planetary confederation. But the Wraith eventually drove them to the brink of annihilation. The ancestors of the Genii sought protection within concealed bunkers that were originally created for wars. It was there that a small number of Genii managed to survive, undetected by the Wraith, where they have made technological developments entirely in secret, even from many of their trading partners (with rare exceptions).
Many generations ago during a culling the Genii successfully disabled a Wraith Dart. Though lives were lost in the event, the ability to resist in the slightest way gave the Genii the seeds of hope. This Dart contained a Wraith data storage device which allowed the race to study their enemy's technology, as well as begin to mount plans against them.
Dr. Rodney McKay suspected Earth was about sixty years ahead of the Genii technologically. Their underground bunkers have been designed to shield radio frequencies.
For many years the Genii have been pushing forward their atomic weapons program, but they have had difficulty purifying uranium to bring it to a weapons-grade quality. According to Commander Cowen, the Genii have had difficulty identifying the molecular structure of the unwanted material, as it is very similar to that of the wanted material. Extended exposure to neutron radiation may have easily left several Genii scientists limited to a short lifespan.
Despite technological developments in atomic technology, the Genii have been greatly interested in Earth's weapons, particularly C4. Originally suggesting its primary use would be to help clear fields for tilling, Chief Cowen eventually added the C4 to Earth vaccines on the bargaining table.
When Major John Sheppard and Dr. McKay discovered the truth about the Genii and their two-faced identity, Cowen revealed that typical trespassers would have swiftly been dealt with. But Sheppard pressed that both societies ultimate enemy was the Wraith, and that attacking each other would only rid the Wraith of possibly two of their foes.
A joint strike force was devised and executed on a Wraith hive ship, but with the loss of Tyrus, a Genii officer, (believed to be because of Teyla Emmagan) the last seeds of mistrust were sewn. Since that time the Genii have executed an attack on the city of Atlantis during a hurricane, failing to take the city, and lost more than sixty soldiers in the process, most at the hands of John Sheppard himself.
The Wraith finally came to cull the Genii homeworld, but their weapons were not prepared at the time. With advance knowledge of the incoming attack, the race was able to deactivate the underground reactors before they were detected. Though hundreds of lives were lost on the surface, thousands more survived in the bunkers below.
The Genii eventually managed to test their nuclear warheads on the Wraith. Six days following the culling on their world Elizabeth Weir brokered an agreement with officer Prenum of the Genii. Prenum was resistant, as the Genii had already survived the Wraith attack. But Weir convinced him that his weapons needed to be tested before another attack could come and claim more Genii lives. Two warheads were sent to Atlantis, and one was used to successfully destroy a hive ship.
The Genii are covert allies of the Manarians, a culture who may have once belonged in the Genii confederation. It is through the Manarians that the Genii successfully infiltrated Atlantis, but they themselves were forced to evacuate in fear that a tsunami would destroy the city.
Throughout the galaxy the Genii are known for their tava beans, and frequently trade them with other worlds.
Underground - With help from Atlantis, the Genii successfully retrieve a Wraith data storage device, but it is taken by Sheppard's team.
The Storm - Commander Kolya and his forces are sent to Atlantis to take the city while their numbers are dramatically reduced.
The Eye - Following a failed attempt to protect Atlantis, Kolya and his men are driven from the city to avoid their own annihilation.
The Brotherhood - Major Sheppard and his team find Genii forces working with the Brotherhood.
The Siege, Part 2 - Prenum of the Genii agrees to send two nuclear warheads to help stop the incoming Wraith hive ships from openly assaulting the city without opposition.
The Lost Boys - Members of Ford's team travel to an alien planet and raid a Genii safehouse to recover some of Earth's stolen weaponry for an attack of their own.
Coup D'etat - The team does not know who to trust when Ladon Radim orchestrates a coup and seizes control of the Genii.
Common Ground - Kolya captures John Sheppard and demands that Atlantis trade him for Ladon Radim, the new leader of the Genii and their tenuous ally, who Kolya regards as a traitor.
Irresponsible - Lucius Lavin pays a group of Genii to take a dive so he can look like a hero. But when he double-crosses them, they demand retribution -- as does Commander Kolya. A showdown with Sheppard leaves Kolya dead.
Remnants - Sheppard is captured and tortured by Kolya and his soldiers on the mainland, only to learn that it was a fantasy created by an alien race.