Janus was one of the most well-known and brilliant Lantean scientists, and his inventions were never orthodox advancements. He took great pride in creating out-of-the-ordinary technological marvels, most of which were either banned or frowned upon by the Lantean Council. He installed a time machine in one of the many Puddle Jumpers in Atlantis, and hid many of his controversial inventions and research (such as a component of the Attero device) in his secret laboratory. He also designed a personal cloaking device and made use of Long-range communication devices and Long-range communication stones. (SGA: "Before I Sleep", "First Contact", "Identity")
When Major John Sheppard and Dr. Radek Zelenka were killed when a Wraith Dart destroyed the Time Jumper and crashed into Lantea's ocean, Janus was able to save Dr. Elizabeth Weir and became her advocate when she met with the Lantean Council. While he argued and defended Weir on her behalf that she should be allowed to return to her own timeline and prevent the Atlantis expedition from falling into the same tragedy again, High Counselor Moros and Melia refused, and Moros angrily condemned his experiments, ordering the Timeship destroyed and the city to be evacuated. (SGA: "Before I Sleep")
Refusing to allow the future Atlantis Expedition to walk into the same disaster she herself had faced, Weir pleaded to Janus to help her find a solution that would save the expedition from walking into the same disaster she faced with herself. Janus agreed and, after doing some calculations, concluded that manually rotating the Zero Point Modules sequentially every 3.3 thousand years would allow slightly more power to be available when the city was visited by the Atlantis expedition and Weir decided to stay behind in the city to perform the task. Janus programmed a stasis pod to re-awaken Weir every 3,000 years or so to allow her to manually turn the ZPM's. He also programmed a Failsafe mechanism into the city should power drop to such a critical level that the shield would fail, so that the clamps keeping the city at the bottom of the sea would release, and the city would rise to the surface. Lastly, he blocked all gate addresses except for Earth so that no one except someone from Earth could dial Atlantis. (SGA: "Before I Sleep")
As Weir decided to stay behind, Janus himself decided to escape with the rest of the Lanteans with crystals of his work which are still not found to Earth, with the hope that his efforts to save Atlantis for the future Atlantis Expedition would succeed, and was the last Lantean to leave Atlantis. Sometime after arriving on Earth he rebuilt his timeship, which would later be used to destroy a Goa'uld mothership and eventually retrieve a Zero Point Module from Ra, which was later used to shield and save Atlantis from the Wraith attack. (SG1: "It's Good to Be King", "Moebius, Part 1", SGA: "Before I Sleep", "The Siege, Part 3")
Shortly after finding Project Arcturus, the Atlantis expedition discovered Janus' protege, Ikaros, a teenage genius who worked with Janus in developing Charybdis, a reality-warping supercomputer that they believed could be used to change history so that the Iratus bug would never evolve, thus preventing the Wraith from existing. However, Janus abandoned the plan because he believed that Ikaros was becoming too obsessed after his family was killed in a culling. (SGA: "Mirror Mirror")
While searching through Janus' lab, McKay found the plans for a personal cloaking device. However, he tells Doctor Jennifer Keller that he doesn't think Janus ever got around to actually making it. Despite this, after months of work in Janus' secret lab, the expedition recovers "tons" of Ancient technology that they still haven't finished cataloging months later. (SGA: "Identity")
Appearing in Teyla's dreams, an Ascended Doctor Elizabeth Weir indicated she had encountered Janus and that he had Ascended himself. She also indicated that Janus had told her of the truth of the Wraith's origin and that he had possibly told Doctor Daniel Jackson as well, but Jackson wouldn't have remembered it. (SGA: "Secrets")
In an alternate timeline, what was left of the Tau'ri after an Aschen bioweapon devastated Earth found a laboratory on a planet where Janus had created many different time travel prototypes following his experiments with the Time Jumper. Among them were pods that used the Stargate itself as an unchanging reference point throughout time to time travel, making the pods glorified beaming devices. An alternate Jack O'Neill, his daughter Jade O'Neill and a Reetou named Ite-kh used the pods to travel back in time to 2003 to avert their future. After succeeding with the help of present SG-1 and Janus' devices, they returned to their time, but not before Jade sent one of the pods on an overload cycle to the planet where Janus' lab was. When the pod exploded, it disrupted the planet's DHD and made the Stargate inaccessible, preventing anyone from ever finding Janus' time travel devices. (Stargate SG-1: Relativity)
- Attero device
- Failsafe mechanism
- Janus' wall sconce
- Time Jumper
- Time loop machine
- Time travel pods
- In Stargate Atlantis: Back to Pegasus 2, by American Mythology, Janus is discovered in a stasis unit at an Ancient moon lab located on Earth's Moon. He is the main villain in this series. At the end of Stargate Atlantis: Singularity, he ascends with Elizabeth Weir after helping to save the galaxy from an alien invasion from another reality.
- In Roman mythology Janus is the god of time among other things.