Ladon Radim is the current Chief of the Genii. Formerly Cowen's chief scientit, he was included in Acastus Kolya's stike team against Atlantis. Radim quickly got the hang of the Atlantean technology, but John Sheppard was able to knock him unconcious when a company came to reinforce the strike team. (SGA: "The Eye")
After the failure of the Atlantis expedition, Kolya began plotting to overthrow Cowen, and took Radim into his confidence. Radim, feeling that neither Cowen or Kolya was qualified to lead the Genii, he betrayed Kolya' information to Cowen, forcing him to go underground, while begining to plot against Cowen. In an elaborate triple cross, he offered a ZPM (which was depleted) to the Atlantis expedition, in exchange for supplies for his "rebellion" against Cowen. Ladon's sister Dahlia and a team went to get the supplies, while Sheppard and Rodney McKay went to get the ZPM. Sheppard, McKay, and a group under Major Lorne were captured by Cowen, who thought that Ladon was still working for him. Cowen demanded the expedition's puddle jumpers, and revealed that Dahlia and the others of her team were dying from radiation poisoning. Ladon intended to detonate a nuclear weapon, killing the soldiers and Cowen, but when he learned that they could save his sister's life, he freed them, allowing the weapon to go off and kill Cowen. (SGA: "Coup D'etat")
When Kolya heard of this, he felt that Radim had stolen what was rightfully his. He captured Sheppard, using a Captive Wraith to feed on him, demanding Ladon in return. McKay and Ronon Dex were willing to turn Ladon over, but Ladon eventually discovered the Stargate address that they were being held in. (SGA: "Common Ground")