The Dark Fortress

The Dark Angels' mobile fortress, the Stone Fortress, was once part of the homeworld Caliban. During a fierce battle, the planet was accidentally destroyed by the First Legion Primarch, Lion El'Jonson, and the Fallen led by Luther. Later, the Lion King's sons used ancient, mysterious technology to refashion the fragments into a "homeworld."

In essence, however, the Stone Fortress was a colossal interstellar warship. Even the Martian Mechanicus could not understand the ancient technology used aboard it. Many suspected that the Dark Angels' Chapter monastery, the Stone Fortress, relied on heretical or ancient technology banned by Terra.

That was why the Dark Angels' mobile fortress, the Stone Fortress, was so often nowhere to be found. It would appear somewhere without warning, launch a devastating assault, then vanish like a ghost once its mission was complete.

Even their fellow loyalists within the Imperium often could not understand what lay behind these strange behaviors of Lion's sons.

Whenever the Dark Angels intervened in a battle, their peculiar actions were steeped in baffling meaning.

But when it came to the Dark Angels' strange behavior, many loyalist sons shared one belief.

They were deliberately concealing secrets. "Secret" was a word every Dark Angel had to keep in mind, and even etch into their bones.

From the moment they joined the Chapter and passed test after test, right up until they became members of the Inner Circle, those known as Lion's sons, the Unforgiven, were given a new mission.

Protect the Primarch's reputation. Protect the First Legion's honor. The First Legion had no secrets!

But now, the secret the Dark Angels had guarded for ten thousand years was on the verge of being exposed.

The evil Chaos Creator, Vashtor, had joined forces with the Chaos warlord Abaddon. Using wicked Warp sorcery in the Idolater System,