A terrible knight who inhabited the castle of Janfrüege in Heinrich von dem Türlin’s Diu Crône.
His castle was enchanted to render any knight who entered powerless. A malicious goddess named Giramphiel sent Gawain to the castle, hoping to destroy him, but Lady Fortune warned Gawain of the danger. As a result, Gawain refused to enter Janfrüege, but insisted that Laamorz meet him outside. Gawain won the combat and secured Laamorz’s fealty.
Laamorz recalls Mabuz in Ulrich von Zatzikhoven’s Lanzalet.
Source
Diu Crône | Heinrich von dem Türlin, c. 1230