Who killed assaj ventress?

Asajj Ventress was killed by the Sith Lord Darth Sidious in the "Star Wars: Dark Disciple" novel. After initially becoming a bounty hunter and attempting to forge her own path, she ultimately faces Sidious, who sees her as a threat to his plans. Ventress's death marks the culmination of her tragic journey from a Sith apprentice to a complex character seeking redemption.