When Lina Inverse first encounters Rudia, he and fellow beastman Vileus are acting as bodyguards for Krotz. When Krotz sees the body of Balgumon, recently killed by Xelloss, he orders Rudia and Vileus to awaken Grouj. The two beastmen refuse, as Grouj has become violent and unpredictable since donning a set of Zanaffar Armor. Krotz then orders the beastmen to fight Lina and her party while he awakens Grouj himself.
However, instead of fighting Lina, Rudia and Vileus ask her to help them. They are afraid of Grouj and fear for Krotz's safety. Rudia offers to lead Lina to him if she promises not to harm Krotz while dealing with Grouj. Before they can reach Grouj, however, Krotz succeeds in awakening him. Grouj's armor consumes him entirely and becomes the second Demon Beast Zanaffar.
Rudia and Vileus join the Slayers in fighting Zanaffar, but both quickly perish. Rudia is killed while attempting to attack the Demon Beast when it appears distracted; his sword bounces off its hide, and it skewers him with a tentacle.