After his return, Sigmund marries Borghild and by her has a son Helgi. As an adult, Helgi meets Sigrun daughter of King Hogni and wishes to marry her. She tells him that her father has promised her to King Hodbrod, so Helgi and Sinfjolti raise an army and invade Hodbrod's realm. In the ensuing battle Helgi kills Hodbrod and subsequently marries Sigrun and usurps Hodbrod's kingship. Sinfjolti then also meets a woman he wishes to marry, and to win her he fights and kills another man, who happens to be Borghild's brother. In revenge Borghild kills Sinfjolti by poison. A grieving Sigmund rejects Borghild and drives her out of his kingdom.