The campaign waged by the New Republic against the Ciutric Hegemony of Prince-Admiral Delak Krennel in 9 ABY, immediately following Thrawn's demise, was known as the Hegemony theater.
Following the death of Thrawn, the New Republic Provisional Council resolved to act swiftly against nearby warlords, aiming to demonstrate that they were not as crippled by the Grand Admiral as some might have thought. Delak Krennel was selected as a target because of his murder of Grand Vizier Sate Pestage years before, and his continued support of his rule through violent purges and the suppression of non-humans.
Many viewed this choice as contentious, given that Krennel had maintained a relatively low profile since ascending to power and had not attempted to expand beyond the Hegemony's borders. With the aid of Ysanne Isard's clone, Krennel had cultivated this image by publicly denouncing superweapons, issuing an apology for the destruction of Alderaan, acknowledging the numerous wrongdoings of the Empire, and offering sanctuary to Humans displaced by the New Republic's policies aimed at reversing Imperial Human High Culture. As the policy continued, they were approached or had been approached by a number of refugee groups and other former Imperials, including Alderaanian refugees. They also had sent word to Gilad Pellaeon about bringing Thrawn's fleet into the Hegemony.
However, the situation began to shift against them with the discovery of plans for the Pulsar Station, a superweapon akin to the Death Star. In actuality, these plans were fabricated and had been planted by the real Ysanne Isard, who assisted a New Republic force commanded by Rogue Squadron in liberating the Hegemony and eliminating Krennel.