After escaping from the Vandals, Battle Force 5 finds Praxion, who initially thought they were threats. He tells them how Vandals devastated their world and that he was the only survivor. When Vert mentions that Sage was alive, Praxion tells them that they could rebuild their civilization. Out of the blue, Zemerik appears and proposes an alliance to get out of that planet. Praxion attempts to attack him, saying that he plotted the destruction of his people. Vert, however, agrees to ally with him.
Eventually, they reach The Cortex, where Praxion apparently attempted to murder Sage as he suggested putting her data container in the wrong compiler. This was corrected by Sherman Cortez, who was familiar with Blue Sentient technology. Sage is eventually restored and Praxion successfully manages to free Krytus while Battle Force 5 was distracted. Upon his return, Praxion appears to praise him.
In the end, Krytus ends up betraying Praxion, as he didn't need his help to free the other Red Sentients or to eliminate his sister and the Battle Force 5. Krytus then threw Praxion off a cliff where he falls to his apparent death.