User blog comment:DirgeOfCerberus111/Adeptus Custodes Vs. Grey Knights/@comment-2253300-20111028201241/@comment-3258762-20111028201523

Supah, Festernius was a Daemon empowered being. Something the GKs are specialized in destroying. The Custodes are not specialized in any way but fight all round, which makes them supperior as the GKs are not meant to fight normal humans other than pawns to defend the chaotic servant.