Suffering from Rheims disease, a rare genetic disorder that manifests shortly after puberty, he became increasingly deformed and infirm, resulting in him withdrawing from public life and refusing the throne. He died at the age of forty one from complications due to the disease.
Throughout his life, Erasmus was sickly and frail. His father Cassius I feared for his life, and eventually advised the boy not to take the burden of kingship upon his shoulders. Cassius the First's reign was long and lasted well into Erasmus' adulthood; by then there were other candidates for succession.
Not long after reaching puberty, Erasmus began exhibiting bizarre symptoms. His features, once considered handsome, grew irregular and deformed. Bony contusions began to grow on his back and head. His skin became leathery and his gums receded, making his teeth appear sharper. The effect made him appear monstrous, and he shut himself away.
Before the strange disease deformed him, Erasmus had married Felicity Morris, who bore him a son, Letholdus II. Felicity was appalled by her husband's appearance and would often refuse even to look upon him.
Eventually she took Letholdus II and went to live with her family in Zemar. Erasmus threatened to raise an army and tear the city apart to get his son back. Cassius I intervened, ordering Felicity to return to her husband. She committed suicide via poison, and attempted to kill her son as well, but he was saved by his nurse, who forced him to vomit up the poison.
Letholdus II was returned to his father, and they lived in a castle in Tyr for the next several years. When Cassius died, Erasmus honored his wishes and declined the crown, citing his poor health; the succession then went to Letholdus II.