Alternatively, an army may include a Legion of the Damned detachment in addition to any other detachments. Other detachments, such as allied detachments, additional primary detachments and fortifications can be taken normally. So, for example, you could field an army with a Blood Angels primary detachment, an allied detachment of Imperial Guard, and a Legion of the Damned detachment. You can include two Legion of the Damned detachments in your army if you wish, but one of these must be the army’s primary detachment.