In Norse mythology, Gram was the name of the sword that Sigurd (Siegfried) used to kill the dragonFafnir. It was forged by Weyland The Smith and originally belonged to his father, Sigmund, who received it in Götaland after pulling it out of a log into which Odin had stuck it—nobody else could pull it out. The sword was destroyed and reforged at least once. After it was reforged, it clove an anvil in half. See Sigurd for more details on the story of Siegfried and Fafnir.
Balmung's most distinct features are his wings as they are unique, representing his having defeated The One Sin.
Balmung appears for the first time in AI Buster, alongside his close friend and partner Orca; when he accompanies Orca to the in-game house owned by Albireo.
Balmung was later chosen by Helba to be one of the key members of Operation Wavebreak, fighting alongside Kite and BlackRose against the Phases.