Battle of Dathomir/Legends

"Prepare yourself, sisters! The war has come to Dathomir!"

- Mother Talzin

The Battle of Dathomir took place in 20 BBY, the final year of the Clone Wars. Count Dooku, seeking revenge for his betrayal at the hands of his former apprentice, Asajj Ventress, and Mother Talzin of the Nightsisters of Dathomir, ordered General Grievous to lead the Separatist Droid Army in an assault on Dathomir aimed at wiping out the Nightsisters. Led by Ventress, the Nightsisters did manage to put up a resistance, however the CIS managed to exterminate nearly every Nightsister.

The battle
After Ventress had been transformed into a real Nightsister, the Nightsisters had a feast at the village, while Grievous landed the army of battle droids on Dathomir. Some Hyena-class bombers destroyed the temple, killing Karis. Ventress and the Nightsisters started the fight against the army of droids, while General Grievous ordered a Defoliator Deployment Tank and some AATs to wipe the Nightsisters out. Talzin sent two Nightsisters to search for Count Dooku's piece of hair, then she asked Old Daka to resurrect the dead nightsisters. With the help of the zombies, the Nightsisters took control over an AAT, destroyed the Defoliator, and made their way to Grievous, where Ventress fought against the General. Naa'leth and Luce were also killed by B1 battle droids. Meanwhile, Talzin used magic to make Count Dooku suffer. Dooku ordered Grievous via hologram to kill Talzin.

Grievous advanced to the cave where Old Daka and Talzin were, he destroyed the cave's secret door, then he killed a Nightsister, stabbed Old Daka, and only missed Talzin. With the disappearance of Old Daka's magic, the zombie army collapsed, and the battle droids killed all the Nighstisters except Ventress. Ventress then asked for help from Talzin.

Aftermath
"Dooku sent his minions to destroy us, but we will survive. We always have."

- Mother Talzin

The remnants of the droid army remained on Dathomir after the battle, with some of them being used by Mother Talzin to create new cybernetic legs for Darth Maul.

Despite the severe casualties, the Nightsisters continued their existence well into the time of the Galactic Civil War and beyond.