Beleg’s name meant 'mighty'. He was also known as Cúthalion, the 'Strongbow'.

Beleg was an elf of Doriath, a renowned archer and chief of the marchwardens. He was skilled with all weapons, but his finest skill was with his great bow Belthronding. He was a brave warrior and aided the Haladin in Brethil, fought in the Nirnaeth Arnoediad and took part in the hunt for the wolf Carcharoth to retrieve one of the Silmarilli

Beleg became the close friend and companion of Túrin whom he found as a youth wandering the borders of Doriath, and brought him before King Thingol at Menegroth to be fostered. Beleg was Túrin’s mentor and tutor and they were for long companions-in-arms. But when Túrin deemed himself an outlaw and fled Doriath, Thingol sent Beleg in search of him, and gave him the free choice of any sword but his own. Beleg chose the great black sword Anglachel, forged by Eöl the Dark Elf.

Beleg found Túrin and his band of outlaws but when Túrin refused to return to Doriath, he gained leave from Thingol to remain as Túrin’s guide and protector.

Returning to Túrin, Beleg found him with his outlaws dwelling with Mîm, a petty-dwarf. Although Beleg was held in honor among the outlaws, Mîm hated him and betrayed them all to the servants of Morgoth. Túrin was taken and Beleg sorely wounded, but being a master of healing he successfully treated his own wounds.

Somewhat recovered, Beleg pursued the Orcs and meeting the escaped elven thrall Gwindor they together rescued Túrin from their camp. Beleg tried to cut Túrin’s bonds with Anglachel, but in the darkness Túrin thought him to be an Orc and fought with him. Túrin mistakenly killed Beleg with Anglachel.

Distraught with grief, Túrin, buried Beleg with his great bow, Belthronding by his side, but took the sword Anglachel, and reforged it under the name Gurthang – Iron of Death. Under this name it was the sword on which Turin himself later died.