During Anubis's preparations for attacking Earth in 2004, Ronan, pretending to be a Rebel Jaffa approached Bra'tac and Teal'c of Chulak, offering his Tel'tak to take them to Proclarush Taonas which SG-1 suspected was the location of the Lost City of Atlantis.
While SG-1 explored the planet, Ronan responded by showing his true loyalty and revealing that he was working for Anubis. He attacked Bra'tac by stabbing Bra'tac's Symbiote pouch in the hope that it would cause Bra'tac a long, slow death yet he was left shocked when Bra'tac revealed that he no longer carried a symbiote.
As such, a brutal fight between the two soon erupted with Bra'tac gaining the upper hand and stabbing Ronan with the wound killing Ronan although Bra'tac was saved thanks to the healing powers of Colonel Jack O'Neill. (SG1: "Lost City, Part 2")