Dion Sendai was born knowing his lot in life and relished that knowledge. He was the third-born son and worshiped his older brothers. He was another in a long line of alchemists that stretched back nearly to the beginning of the craft. He had time for study and learning, and knew that one day he would follow in his father's footsteps into a professorship in the alchemy department at the College of Science.
As it tends to do, life changed. When he was six, his next eldest brother died in a lab accident. As he was finishing his work in school, his father was appointed to the Lordship of Pyria. No longer was he certain he was destined for the comfortable life of a professor. He became his father's assistant in everything, as he had been his apprentice in alchemy, though the bulk of responsibility for the lordship was borne by his eldest brother, Pyrphoros.
As his father grew older, he grew careless with the exacting standards of safety he had always maintained and enforced upon his students and family. After an accident involving glass fumes, his children determined Ister was no longer capable of working in the lab without supervision. This responsibility fell largely to Dion.
Despite Dion's best efforts, his father eluded him frequently to spend time in the lab alone. One afternoon, the Sendai children's fears were realized when Ister's experiment exploded, destroying both him and his lab. Dion rushed into the resulting conflagration in an attempt to rescue his father, but his efforts were for naught. As a consequence, Dion sustained burns on 25% of his body, most of them on his chest and neck, some of them extending up to his jawline. His recovery was slow. During his convalescence, his eldest brother was murdered.
Grieving and scarred, Dion found himself in a position he never expected would fall to him. It was a responsibility he never desired nor planned for, and he resented it with every fiber of his being. While in recovery, his responsibilities fell to his younger sister, Gwenn, until he was well enough to take up his duties. She still acts as his representative in Gateway on all matters and in Pyria in social matters.