The Bastion Fleet, originally known as the Admonitor task force was the personal armada of Grand Admiral Thrawn from 3 ABY until his death in 18 ABY. It was formed from Thrawn's original fleet which he used to map the Unknown Regions from 3 ABY to 6 ABY; during this time, it only consisted of the Imperial I-class Star Destroyer Admonitor, twenty Victory-class Star Destroyers and several support ships. After the Grand Admiral returned to the hidden Imperial fortress world of Bastion, nine other Imperial-class Star Destroyers joined it. This reinforced fleet participated in the initial battles of the Thrawn campaign. In 9 ABY, two Executor-class Star Dreadnoughts were assigned to the fleet, but the iconic Star Destroyer Chimaera retained its role as a command ship.