Don't forget the support ships infinite succor.--Halo3Halo3
At the beginning of Halo 2, the Arbiter (ex-supreme commander) says that he followed the Pillar of Autumn with all the ships in his command, but not all the vessels who assaulted Reach followed the Pillar. Even later, I don't think the number of ships around Halo was bigger than a hundred. It is also said in the article on the Covenant Fleet that a fleet is usually composed by a hundred ships, not more. At last, the flasgship of the fleet that attacked Reach was destroyed. So, I think the fleet at Reach was a combined fleet, and was not entirely under command of the future Arbiter. The Fleet of Particular Justice is, maybe, a third of the staships present, one of the three or four fleets included on the fleet of Reach. Maybe it was under command of an Imperial Admiral, but he died with the destruction of his flagship.
Actually there was one flagship.If there was more than the book would of mentioned.I doubt there was more than one imperial admiral and also flagship can technically go to any ship as the user Halo3 20:55, 7 March 2007 (UTC)--rot said and also the fleet was larger than 100 not to mention there can only be one flagship and imperial admiral most likely being the arbiter.