A Flail of the Unforgiven is an archaic Power Weapon commonly utilised by the Knight Masters of the Dark Angels Space Marine Chapter's elite cadre of Deathwing Terminators known as the Deathwing Knights. The Knight Masters eschew the usual Power Maces preferred by their fellows in favour of these brutal Power Flails. These weapons are carried as a badge of office for a Deathwing Knight Master and are a reminder to all the Fallen Angels of their ultimate fate at the hands of the Dark Angels and their Unforgiven Successor Chapters.
- Codex: Dark Angels (6th Edition), pp. 45, 62, 81