The High Charity defense fleet was a formation of many Covenant Navy ships and multiple fleets around High Charity to defend it. The fleet had hundreds of ships protecting High Charity at any time, reflecting the holy city's importance. A ship approaching High Charity had a nanosecond to submit a security code, or it would be destroyed by the sheer might of the fleet and High Charity's defenses. During 2552, the Second Fleet of Homogeneous Clarity served within the High Charity defense fleet.
This fleet was completely disbanded in the Battle of High Charity when the Great Schism erupted in the Covenant. There was a large battle within the fleet, ending with most of the surviving Covenant Loyalist ships going to Earth, and the Covenant Separatist ships staying to attempt to contain the Flood. These attempts failed, however, when a single Flood Ship broke through, and headed towards Earth, with a small battle group of Covenant Separatist ships in pursuit.
It is unknown what remains of the fleet after High Charity, under the power of the Gravemind, forced its way out of quarantine and passed through the Portal at Earth. The surviving portion of the fleet may have continued to undertake combat activities against the Brute-controlled portion of the Covenant Fleet up until the War's end.