The Ilum showdown was an operation aimed at stopping the Dread Host and Sith Lord Tagriss from releasing the energy locked within the final Seeds of Rage. A group was sent to stop him, made up of individuals from the Jedi Order, the Galactic Republic, and the Sith Empire. They encountered a twisted Sithspawn experiment in the Ilum Temple, which futilely used four tentacles to try and fend them off.
Interrupted from his meditation, Tagriss was faced by the team; he fought them and tried to empower himself with the seeds' power, but he was killed during the fight. The seeds were then taken back.
In the "Alchemy of Evil" mission on Ilum, which is the final one, Imperial players have a choice: they can use the corrupted Jedi forge to combine the Seeds of Rage into a single item that turns into armor when the mission is over (the dark side choice), or they can simply give the seeds back to Darth Acina unharmed, who will then put them in a safer place on Ziost (the light side choice).