InGylfaginning (The Beguiling of Gylfi), the god Freyr is forced to fight weaponless against the giant Beli, since he has given his sword to his servant Skírnir before sending him to court Gerðr for his master. Freyr eventually manages to kill the giant with the antler of a hart (stag).[3][1]
According to scholar John Lindow, the killing of Beli is part of an older myth that has been lost and "can be glimpsed only in passing".[1]
Elsewhere in Skírnismál (The Lay of Skírnir), Gerðr complains of the slaying of her brother by Frey, which some scholars have interpreted as evidence that she was the sister of Beli.[1] According to Orchard, "it is clear that Gerd’s reluctance to accept Frey’s favours is based in no small part on her grief for her unnamed brother, whom Frey might have killed. It is therefore possible that Beli is the brother of Gerd, although Frey’s traditional weaponlessness, most tellingly at Ragnarok against Surt, renders the identification uncertain."[3]