Dagrah

This ancient dragon roamed the skies, protecting travelers by the light of the moon. He was originally a neutrally aligned creature but after facing his inevitable death he felt compelled to extend his life. He attempted to complete the process of becoming a dracolich in order that he could be immortal but the process somehow fell short. His essence was captured inside a large diamond, next to where his corpse began to decompose. It is believed that Dr. William Birkin located Dagrah's underground lair and held the dragon captive, utilizing the stone's power to fuel his experiments.