The so-called "replacement warlords" were the beings who succeeded the thirteen warlords that had been executed by Admiral Daala in 12 ABY. They were located in the Deep Core, where industrial infrastructure had largely been left intact and where planets teemed with Imperial subjects. Few of the replacements possessed the strategic talents or resources commanded by those killed by Daala, but compensated with base cruelty and repression.
Following her defeat of Moff Getelles's forces, Daala returned to the Deep Core, and became the leader of a coalition of these warlords, eventually leading strikes into New Republic space. Brakiss became a neutral power-broker among them following his involvement in the Almanian Uprising.
However, the squabbling warlords could not provide a united front even with Daala's leadership, and the New Republic's Fourth Fleet, led by General Garm Bel Iblis, launched a crippling series of assaults on their perimeter. In the last assault, Bel Iblis defeated Daala, forcing her flagship to escape into hyperspace; it remained unaccounted for.
However, the replacement warlords themselves remained, and re-organized themselves as the Second Imperium.