Ewein Avoutres, Yewains; Yvain les Avoutres, Yvain of Lafultere, Yvain the Adulterer; Yvains li Avoutres, Yvains li Batarz; Yvonet li Avoutres, Yvonet l’Avoltre, Yvonet li Aoltres
He left home with his brother to join Arthur’s service, even though his father was involved in a rebellion against Arthur. He fought in the Saxon wars and was knighted by Arthur for his service. He further participated in the wars against Rome, Claudas, and Galehaut. He had a son named Cahus, who died as Arthur’s squire.
During the Grail Quest, Yvain the Bastard adventured with Gawain and Galahad, and he helped Gawain and Gareth, his cousins, liberate the Castle of Maidens by killing the seven knights that ruled there. Late in the Grail Quest, Yvain was killed by Gawain when they jousted together, unaware of each others’ identity. Malory, in an obvious mistake, states that Yvain the Bastard appeared at the healing of Sir Urry, which occurs after his reported death.
In the Scottish Lancelot of the Laik, Yvain the Bastard and Yvain les Avoutres (Yvonet li Avoutres) are two separate characters.