Truth's fleet

After the Flood landed and the Separatists fleet overwhelmed High Charity and its defensive fleet, the surviving Jiralhanae-held ships, consisting of three Assault Carriers and twenty-seven CCS-Class Battlecruisers, managed to follow the Prophet of Truth and his Keyship to Earth, where they destroyed the remnants of humanity's orbital defenses. Rather than glass the human world from orbit, the ships held position over East Africa, though some forces branched out further into parts of North America in search of a supposed Forerunner artifact. After the Master Chief joined up with UNSC forces, he spearheaded an effort that pushed the fleet's ground forces further towards their innermost stronghold - a mammoth Forerunner structure, known as the Portal. After the Prophet of Truth activated the Portal, and the Flood attempted to infect Earth, Truth's fleet escaped into the slipspace bubble to the Ark, another Forerunner Installation outside of the Milky Way.

A joint UNSC-Sangheili effort, consisting of at least three UNSC frigates, and nine Sangheili cruisers and an Assault Carrier, managed to follow the Covenant ships a few hours later, eventually destroying them completely, bringing the Human-Covenant War to its end. It is still unknown if any ships survived the space battle, but it might be possible because two Scarabs dropped from the sky to aide the Covenant Loyalist in defending the Citadel.