Formations of Legend
Throughout the Horus Heresy many groups of warriors became figures of awe, committing mighty or infamous deeds that would ensure their names would be remembered. Formations of Legend represent these groups.
Each Formation of Legend belongs to an Army List, and can be included in your Army following the rules for these Army Lists found in the Legions Imperialis Rulebook.
Each Formation of Legend consists of two elements: Standard Detachments and Expanded Detachments. When a Formation of Legend is added to your Army Roster, you can either add only the Standard Detachments for the points cost listed, or the Standard Detachments and the Expanded Detachments, paying the total points cost for the Standard Detachments, plus the additional points cost for the Expanded Detachments. A player may choose not to include every Detachment listed under the Expanded Detachments section, but the points cost is not reduced if they do so.
You can only include each Formation of Legend once in your Army.