The Battle of Acherin took place in the year following the end of the Clone Wars.
The battle began when, having saved a Republic Jedi General from being killed by his own troops, the leaders of the Acherin Separatists quickly came to realize that the emerging Galactic Empire was a much greater threat than the old Galactic Republic.
Organizing their Separatist troops into a resistance force, the inhabitants of Acherin waged a bloody battle against the Empire, leading to heavy losses on both sides. To save some lives in the process, the Empire would utilize single-person Compact Assault Vehicles piloted by droids.
With the planet on the verge of pacification, Imperial Admiral Riwwel refused to accept the Acherin plea for cease-fire, ordering the bombardment of Eluthan, the Acherin capital, as revenge for all his dead troops.
Only the timely arrival of the Jedi Master Obi-Wan Kenobi and Ferus Olin saved the lives of the resistance leaders Toma and Raina Quill. While they fled, the Empire devastated the city and claimed the planet.