The Maledictum was an ancient stone or key that the Eldar of Craftworld Biel-Tan used to imprison a mighty Daemon from the Warp on the planet Tartarus. The Chaos Space Marines of the Alpha Legion gained knowledge of the Maledictum and found themselves on the planet Tartarus in their search to release this daemon. The Eldar, under command of Farseer Macha, after forseeing what the Alpha Legion were trying to do, went to Tartarus in an attempt to stop the forces of Chaos.
The Blood Ravens 3rd Company under the command of Captain Gabriel Angelos were originally sent to Tartarus to quell an Ork invasion, but after gaining knowledge of Chaos's presence on the planet make it their priority to hunt them down. In this hunt the Blood Ravens also came across the Eldar, who were trying to protect the clues to finding the Maledictum, by killing all who opposed them. Farseer Macha warned Captain Gabriel Angelos, but the Blood Ravens were to focused on destorying the Alpha Legion and not their true purpose on the planet. But they couldn't withstand the assault of the Blood Ravens and the Eldar's strike force was crippled,but this gave the Alpha Legion their chance to unlock the clues while the Eldar and Space Marines were fighting amongst themsleves.
Ultimately the Alpha Legion on Tartarus were destroyed, but at a grave cost. When the Chaos sorcerer Sindri Myr harnessed the power of the Maledictum, Sindri was overtaken by a mighty Daemon Prince. The remaining Blood Ravens and the shattered remains of Farseer Macha's strike force formed a temporary alliance in an attempt to destroy what Sindri had become. Ultimately they destroyed the Daemon Prince, but in a crucial last decision Farseer Macha warns Gabriel Angelos not to destroy the Maledictum, but he ignores her and shatters the maledictum anyway. Thus unleashing the terrible daemon on the rest of the galaxy.