The year is 30,021. Mankind's spread beyond the stars, lead by the almighty force of the God-Emperor of Mankind and his Space Marines descended into the bloody mire of the Horus Heresy, brother pitted against brother and God clashing against God. Seven years after the Emperor was interred upon his Golden Throne, Roboute Gulliman, the Master of Ultramar has finished his seminal work: The Codex Astartes. This great work details how the vast Space Marine Legions must be assembled. For the First Legion- reeling from the loss of their Primarch, Lion 'El Johnson, has agreed to abide by these new rules, and as such the Sons of the Lion, now the Unforgiven, find themselves broken into individual chapters.
The Lions of Absolution, from the ruins of Caliban, rise to their feet. Although a new chapter, with reliquary and library far emptier than those of their progenitor chapters, will carve their name, by blood and bolter fire, into the pagers of the Imperium's history books. In the name of the Emperor, who the Unforgiven must redeem themselves in the eyes of, in the name of their deceased Primarch, they will destroy heresy wherever they find it- the Emperor wills it.
Welcome, brothers of the First Legion. Although no longer of the Dark Angels, the Unforgiven nonetheless share the shame of the fall of their brothers. As the Lions of Absolutions are formed they too must take up arms against their former companions, to give them the Emperor's peace once and for all and redeem themselves in the eyes of their father.
The Dark Angels has not left their new chapters with nothing. The Lions of Absolution start with a tried-and-tested armoury, including enough suits of terminator armour and bikes to continue their parent chapter's unique organisation of their first and second companies. Although marines of the Lions of Absolution are unlikely to see the remains of Caliban again, they instead earn the chance to become the first names in a long line of superlative service- names echoing on in history for thousands of marines to emulate. No astartes could ever receive a higher honour.
The Lions do not have long to linger however. The Lord Commander of the Imperium has given them an important task- crush the last few planets that have not learnt of the death of the treacherous warmaster in the Segmentum Tempestum. To prevent these planets from dragging more down with them into another civil war, action must be swift, decisive and brutal, crushing all dissent and restoring the Emperor's light to its proper place.