|“|| Congratulations, fellow traveler, on your discovery of our secret compound... *Alarm sounds* Your markings betray you as a follower of the false Prophet; of Kane! Identify yourself or face the consequences!|
- Marcion to LEGION's forces
|“|| Kane was a coward, and a traitor, who long ago lost faith in the purity that is Tiberium! His violent demise was the result of his own lies and blasphemies... And he will be brought down to the pit of Hell, and all there would stare at him, asking: "Can this be the one who shook the Earth and kingdoms of the world?"|
- Marcion speaking in a video during the mission briefing.
|“|| Yes, I am the One! I am the true prophet of the power of Tiberium! Brother Marcion will be brought down to his knees and you, my child, will be the one to strike him down! Show him no mercy - for he deserves none.|
- Kane briefing LEGION.
After the Firestorm Crisis, the Brotherhood of Nod was seemingly broken and splintered into various factions without the will of Kane who was believed to had been killed by the Global Defense Initiative. Now but a shadow of its former glory, the Brotherhood was no longer a challenge to GDI who instead focused their efforts in reclaiming the planet from the ravages of Tiberium. Amongst the many factions that arose were the feared members of the elite Black Hand who had slain Kane's rightful successor Anton Slavik and began following a new leader known as Marcion. In order to negate any threat posed by him, GDI targeted Marcion's vanity and made him renounce Kane as the ruler of the Brotherhood and take command of it himself. Denouncing Kane as a traitor, Marcion led the Black Hand and many other members of Nod through his charisma as well as exceptional oratory skills.
However, unknown to many, Kane had in fact survived, and was recuperating in the shadows. He made use of a small group of loyal followers to help reunify the Brotherhood once more under his will. One of the many agents at his disposal was the advanced artificial intelligence known as LEGION who had demonstrated its effectiveness by instigating the Rio Insurrection which provided many new converts. Now, Kane decided to strike against Marcion at his secret compound and bring the Black Hand once more into the fold.
During the operation, loyalist Nod forces were deployed to bring back the renegade Marcion as well as his followers in the Black Hand. After arriving, Marcion believed the newly arrived Brotherhood forces to be fellow pilgrims but after he discovered the markings; he learnt that they were loyal to Kane. This led to Marcion contacting LEGION, demanding the A.I. to identify itself.
At the time of this battle, the GDI's Steel Talons had set up hidden uploading scanners, which would call in reinforcements should it detect Nod forces in the vicinity (Marcion's forces had circumvented the scanners somehow).
After building up a force, LEGION assaulted the Black Hand's base. The A.I. also destroyed the Steel Talons' scanners. After punching through the defenses, and eliminating several heroic Black Hand units, LEGION had broken the first defenses. Another objective was given to destroy Marcion's statues, to bring down his reputation. With that done LEGION eventually destroyed the Black Hand's stronghold. Shortly after destroying it, Marcion was nowhere to be seen. Marcion was escaping through a bunker to safety. His convoy was eventually destroyed, and his transport was secured. Kane then ordered that Marcion be brought back to Nod. In the transport, Marcion made a speech to his Black Hand followers that Kane was the true messiah. He confirmed that GDI had corrupted him. Marcion's transport was brought to safety, and the heretic was brought back into the fold.
The defeat of Marcion allowed the elite soldiers of the Black Hand to return to their rightful place as disciples of Kane. Marcion becomes the figurehead leader which allows Kane to operate from the shadows.