A cruel giant, prone to engage in plunder, rape, and murder. He murdered his own parents and became lord of the Hill Castle.

After falling in love with a maiden, he promised to cease his wicked activities, but he soon regretted his vow. Yvain was tricked into battering his shield, hanging outside of the Hill Castle, giving Malduit an excuse to begin another rampage. Yvain tried to fight him in single combat, but was imprisoned in the Castle Penning (Peningue) by people furious that he had released the giant in the first place. Eventually, Bors arrived, slew Malduit, and freed Yvain.