By the year 2552, Rho 'Barutamee was made the Supreme Commander of the Fleet of Valiant Prudence which included the flagship he was stationed on, the CSO-class supercarrier Long Night of Solace. Using zealots from the Ministry of Fervent Intercession, he hand picked and created his crew called the Devoted Sentries.
Battle of Reach
This fleet would be the scout force sent to Reach ahead of the main Covenant invasion fleet. This placed Rho as the commander of the first assault on Reach, this command was later taken over by Thel 'Vadamee when he arrived with his fleet.
Secretly however, he wasn't interested in the Covenant's campaign against humanity, and instead was hunting relics to try and find the fabled Maethrillian. He was worried about an incoming, much larger fleet, that would rob him of his chance to get these artifacts.
The Long Night of Solace continued its assault on the surface of Reach, where the troopers of the UNSC Army, under the leadership of Noble Team, destroyed the cloaking device of the supercarrier. The Fleet's vessels attacked the UNSC Army's garrisons before retreating into orbit. The Long Night of Solace was the primary target of Operation: UPPER CUT, which could only be reached via the smaller ship the Ardent Prayer loaded with a bomb.
The fate of Rho is unknown, but he presumably died on the Long Night of Solace with his entire crew and Jorge-052 when the slipspace rupture ripped the vessel apart. His lieutenant, Kantar 'Utaralee, took over the fleet after his presumed death.