The Great Crusade and Heresy

Trajann Valoris walked towards a massive golden gate adorned with statues of heroes that even Dante couldn't identify. Dante could only surmise that the figures carved into the gate were indeed heroes. On each side of the gate stood large walker robots, slightly hunched with their heads leaning forward from their shoulders. The robots were predominantly red with the left shoulder guard in yellow with black lines and a triangular logo resembling a honeycomb, with the outer part bearing a bee emblem.

"Apologies for the increased security, but we cannot afford to leave any room for the Horus Heresy to repeat itself," Trajann Valoris said, providing a hand gesture, and the gate opened.

"Welcome to the Hall of Heroes. Here, we document the most heroic battles from various Space Marine Legions, Astra Militarum units, and other forces," Trajann Valoris explained.

Dante observed the massive sculptures of heroes' faces, and although the hall was beautiful, it was constantly guarded by Custodes on relentless patrol. "Forgive me, you've arrived during the Blood Game. Several Shield Host Captains are currently tracking a Custodes engaged in skirmishes, attempting to ascertain... Ah, it's over, isn't it?" Trajann Valoris addressed a female Adeptus Custodes.

"I thought all Custodes were male," Dante remarked.

"In reality, there are a few female Custodes," Trajann Valoris said, leading the way to a room with a large golden gate. He input a code, and the gate opened.

"The Emperor of Mankind is inside this room. Please mind your words and etiquette... ah, perfect timing," Trajan Valoris said, spotting someone. The person stood four meters tall, had short blond hair adorned with green leaves. "Captain General, is this the individual?" the person asked. Dante observed the individual wearing blue power armor with a double-headed eagle logo on the chest and a golden halo. Ornamentation with an inverted Omega symbol adorned the shoulder guards, with the name Guilliman.

"Lord Commander, he's the one," Trajann Valoris confirmed. "Father has a talent for recognizing those with strength," Roubute Guilliman said.

"Father? Wait a moment, throughout the journey, I saw..." Dante began.

"Let's head inside first; I'll explain everything, and you'll meet Father at the same time," Roubute Guilliman interrupted, entering the room. Dante quickly followed suit.

"Ah yes, I was asking about the Battle of Mount Ararat... the final battle of the Thunder Warriors... so what happened?" Dante asked. "The Space Marines are fully trained and deployed to the battlefield, the Emperor created the Primarchs with the task of leading the Space Marines. What I remember is landing on Macragge and being raised in the House of Guilliman," said the Primarch as he walked towards a pyramid with a very large chair at its peak. "When the Emperor arrived, he said that Macragge would become part of a greater Imperium. I accepted that offer and led the 13th Ultramarines Legion," said Guilliman, Dante only looked into the blue eyes of Roboute Guilliman.

"Legion 13...? Does that mean there are others still?" Dante asked. "Of course, there are still others, unfortunately some turned traitor, went missing, or perished," Guilliman said with a flat expression. "How many are left then?" Dante inquired. "There are 17 others... sadly, half of them turned traitor and followed their chosen Chaos Gods..." Roboute Guilliman replied, "If only Horus Lupercal hadn't been wounded and taken to the Serpent Lodge by the Luna Wolves... perhaps this chaos wouldn't have occurred..." Guilliman mused, "What exactly happened?" Dante asked.

"When we were all found, the Emperor was busy uniting all the scattered human colony planets in M30," Guilliman explained. "The Great Crusade was the pinnacle of all of us, until I was assigned to burn Monarchia on the planet Colchis by the Emperor himself," Guilliman said as he walked closer to the large pyramid. "Lorgar, through his 1st Captain Erebus, trapped Horus and turned him into a worshiper of the Chaos Gods. It seems it had been long planned by Lorgar since the punishment by the Emperor of Mankind," Guilliman continued. "Ferrus Manus fell first on Isstvan V, killed by Fulgrim. I, along with Lion El'Jonson and Sanguinius, were delayed because we had to deal with the terror of Konrad Curze," he said, continuing to ascend towards 75% of the pyramid.

"This is the current Emperor of Mankind; physically, he has become a skeleton," Guilliman said, pointing to a massive throne with a seated skull. "The physical form of the Emperor of Mankind; you met his soul while in the Warp," Roboute Guilliman explained. "Father, this is the person you wished to meet in person," Guilliman said, kneeling with one knee, and Dante quickly followed suit.

"Dante... friend... strength... custodes... new..." the skull spoke, "Trajann... armor..." the Emperor continued, then fell silent. A Custodes appeared before Dante and Guilliman, "Dante, the Emperor has been waiting for you to come here," the Custodes said. "The Emperor of Mankind wants you to join the Adeptus Custodes, but he knows you can be more than just an ordinary Custodes," the Emissary said. "Father indeed doesn't misjudge people. Since the first time I met you, I could sense something different," Roboute Guilliman said. "It seems being a Custodes will be quite enjoyable," Dante said with a slightly joyful tone.

Trajann Valoris entered the Golden Throne and knelt at the same location as Guilliman and Dante. "Captain General, the Emperor has entrusted you with a task," the Emissary said to the Captain General. "Captain General Trajann Valoris is ready to receive the task from the Emperor directly," Trajann Valoris replied. "You will train Custodes Dante until he fully masters the combat techniques, negotiation skills, and all that is required by the Adeptus Custodes," the Emissary said. "Trajann Valoris fully accepts this task," Trajann Valoris affirmed.

"Come with me..." Trajann Valoris said as he descended and quickly exited the Sanctum Imperialis, passing through the Hall of Heroes. "Actually, there were 20 Primarchs created by the Emperor of Mankind," Trajann Valoris explained. "The 2nd Legion and 11th Legion have similarities with the 13th Legion and 6th Legion, but if they were to argue... or if, worse, the Horus Heresy occurred, it would just be considered a warm-up," he continued. "Also, if Primarch Magnus had physically met the Emperor directly without using magic from the Warp, there might have been a small-scale civil war ensuring the destruction of the House of Navigator," Trajann Valoris added.

"Emperor, did he prepare a project?" Dante asked. "At that time, yes, the Emperor had prepared the Webway Project to replace Warp Travel. The Emperor was ready to negotiate with the Eldar residing in Commorragh, but Magnus damaged the Psychic barriers set up by the Emperor," Trajann Valoris explained. "The first and most severe defeat we experienced at that time was due to the multitude of daemons pouring out of the Webway. Many of our comrades fell," Trajann continued. "In that case, I want to start training immediately. The sooner I can kick a few enemies of the Imperium, the better," Dante said, and Trajann Valoris laughed happily.