Battle of Harmony

The Battle of Harmony was the first battle the newly formed Black Legion fought, under the command of Ezekyle Abaddon. Harmony contained the Canticle City, which was the largest base for the Emperor's Children, and it was here that Fabius Bile took Horus's body to be cloned.

The Black Legion opened the battle in spectacular fashion by psychically dropping an entire battle cruiser on the Canticle City, courtesy of Abaddon's Thousand Sons sorcerers. After scattering the Emperor's Children fleet with the Vengeful Spirit, Abaddon and his men boarded Bile's ship and destroyed the Primarch cloning project. An irritated Bile unleashed his perfected clone of Horus against the Black Legionnaires, who cut a bloody swathe through Abaddon's forces before the latter killed him with the Talon of Horus.

What little power the Emperor's Children retained after the Battle of Skalathrax was destroyed here, and they have never regained their former strength.