Ronon defended his world during a devastating Wraith culling seven years before he joined the team, but was swept up in a culling beam. He was taken aboard a hive ship, but when a Wraith attempted to feed on him something forced it to stop. Instead of dying as food, Ronon was made a Runner: The Wraith implanted a transmitter in his back and let him go, hunting him across many worlds for sport, for training, or for some other, unknown reason.
Ronon possesses a rather unique gun with both stun and kill settings. A cunning and skilled warrior, he hunted his Hunters, killing many Wraith. But he could never return home, nor could he stay in one place for too long. Once, when he stopped to eat a meal and get a night's sleep in a village, the Wraith showed up the next day and destroyed it.
Dex captured John Sheppard and Teyla Emmagan when the team came to P3M-736 to search for Aiden Ford, who himself hunted and killed the Wraith pursuing Dex. They agreed to help him, and brought Dr. Beckett to the planet to remove the Wraith tracking device from his back. Now, he is free to stay in one place. Upon learning that the Wraith destroyed Sateda, Ronon decided to stay in Atlantis.
Ronon's physiology is unique. Not only can the Wraith apparently not feed on him, but he also fully recovered from a stunner blast within seconds. He is a dangerous ally to have, as his abilities and personal motivations remain unknown. But he is loyal to Sheppard and his new friends, and puts the fight against the Wraith -- all Wraith, in any form they might take, anywhere and at any time -- as his highest priority.
Runner - The team meets Ronon when the runner captures Sheppard and Teyla, then saves McKay from an irate Aiden Ford.
Trinity - Ronon and Teyla travel to Belkan, where they learn approximately 300 Satedans survived the destruction of their world.
Michael - Ronon's uncompromising hostility to young Michael Kenmore is explained when the amnesiac man discovers he is really a Wraith.
No Man's Land - Ronon and McKay are captured by the duplicitous Wraith, but Ronon manages to power out of his cocoon prison and eventually escape.
Sateda - Ronon is public enemy number one on a planet to which he once inadvertently led the Wraith. When they turn him over to the Wraith, Ronon is returned to the ruins of his homeworld and is made a runner once again.
Phantoms - Ronon turns his weapon on his friends when a Wraith device alters his perception.
The Return, Part 1 - Anxious to keep fighting the Wraith after the Ancients reclaim Atlantis and send the rest of the team back to Earth, Ronon stays with Teyla but refuses to join forces with the Genii.
Reunion - Ronon is reunited with a group of fellow Satedan survivors, and decides to leave Atlantis to join their efforts against the Wraith. But when he learns they are Wraith worshippers, Ronon is forces to fight his own friends.
Midway - Ronon reacts against Teal'c when the Jaffa warrior arrives to give him advice in how to handle an impending evaluation by the I.O.A. But the two must join forces when the Midway Station is overcome by Wraith trying to reach Earth.
The Last Man - In an alternate future, Ronon leaves Atlantis and assembles and trains his own fighting force to take on the Wraith, ultimately sacrificing himself when he is unable to escape a Wraith facility during a mission.
Broken Ties - Ronon's traitorous old friend Tyre captures him and hands him over to a Wraith, who tortures him and turns him into a Wraith worshiper. When the team gets him back, he must face a tortuous withdrawal process.
Tracker - After helping to rescue her from a kidnapper, Ronon learns that Jennifer Keller is not romantically interested in him.
Enemy At the Gate - When the team infiltrates a Wraith super hive attacking Earth, Ronon is stabbed and killed -- only to be revived for interrogation by a Wraith.