Moody the Murderous was the former Chief of the Murderous Tribe, who was also Termagant's father and Fishlegs' maternal grandfather.
According to the Deadly Shadow, Moody was a very fierce chief of his tribe; his daughter Termagant however, was more compassionate. Moody had the belief that only his heirs should marry heirs of chieftains. Termagant eventually fell in love with a Fisherman from the Peaceable Country (who is later revealed to be Alvin the Treacherous). They married, much to Moody's fury. However, Alvin left Termagant, and she was pregnant with his child. She believed that her son would be a handsome brave Viking hero, heroic and poetic. However, when the child was born, he was pronounced a runt.
Moody had no choice but to banish his grandson. However, Termagant secretly ordered her Deadly Shadow to take Fishlegs to Hero's End (the Final Resting place of Grimbeard the Ghastly). The child was exiled, and Moody was proud that the runt was gone.
When the Deadly Shadow ended up losing Fishlegs, and only discovering that Termagant died later. In anger, and blaming her father for the misfortune, the Deadly Shadow killed Moody. They hid in the mountains for fourteen years before joining the dragon rebellion.