The Grim Angels are a special type of Angel. This breed was created solely for combat; they are living weapons, and seem to exceed even the Gods in raw power. Each Grim Angel wields a Diviner crafted specifically for them; these Diviners are the very source of their power. However, to wield these great weapons and be branded a Grim Angel, one must sacrifice a piece of themselves. The angels are 100% devoted to serving their superiors however they can.
During the genocidal war of Ragnarok, the devastating might of the Grim Angels barely won Asgard the battle. In spite of this, the Gods have all died, leaving the Seven Magi as the reigning powers in Asgard. Creating a Grim Angel is a long-forbidden taboo, because of their great power, and the sacrifices that must be made. After the war, they were sealed away to sleep indefinitely until their power is needed once again. During the events of Riviera: The Promised Land, three of them were dispatched by Hector: Ein, Ledah, and Malice.
Grim Angels have several notable physical features. The most obvious of them is their large, black wings and pale skin. Their weapons and clothing are also distinct and make them recognizable.
The Grim Angels had their biggest in-game role in Riviera, however they are referenced in the PSP version of Yggdra Union. An optional, non-canon Battlefield available only in a Hard mode playthrough provides additional insight into what was taking place in Asgard, namely due to Hector's scheming. It is heavily suggested that No. 367 is a primal form of Malice, and that Hector manufactures them by technological means. If she is defeated, Yggdra's army will be such a great threat that Asgard would have no choice but to awaken the Grim Angels once again. Whichever side prevails in the end is left ambiguous, but it can be inferred that the Grim Angels won the battle once again.
The theme of the Grim Angels is "The Angels Fortell Their Demise". It plays during Angelic Advent and when fighting against Ledah and Malice.