Major Ernesto Medeiros is a template for a series of Brazilian Van Neumann probe replicants and an antagonist in first book. His first ship is called the Serra do Mar, destroyed by Bob in 2144 at Epsilon Eridani. It is presumable that each ship has its own name, rather than the replicant controlling it.
Medeiros is absolutely loyal to directives of Brazilian Empire, as shown in his only communication with Bob, so while he is also restrained by failsafes he can't remove, he also feels joy in destroying his enemies. Strangely, he curses in Spanish, although the state language of Brazil is Portuguese.
Due to militaristic nature, his ships are more equipped for combat rather than reproduction and he is able to adapt to tactics of Bob and shouldn't be underestimated. Fortunately, he cannot replenish high-tech ammo, like nuclear missiles, but still can be dangerous when cornered.
He and his base of operations was discovered and chased out of Alpha Centauri.
He and his clones are also responsible for ambushing and killing Milo in 82 Eridani in August 2165, forcing Bob to forward the backup system.
He is successfully pushed out of that system by initiatives led by Khan and Loki in 2185 and 2195, in upgraded FAITH-3 ships.
He resurfaces in 3.21. in 82 Eridani again, June 2223, having attacked Mack. He is defeated again by both the Bobs and the humans on Valhalla and Asgard. Strayed ships are still existant, so it is possible that he recuperates his capacities at distant systems or in interstellar space.