James Xavier was a doctor who lived in Victorian England and was slightly skeptical of the theories of a scientist named Charles Darwin about evolution and natural selection. He frequently debated these theories with his close friend, the brilliant Dr. Nathaniel Essex, who was obsessed with Darwin's theories. Essex's obsession with the theories led him into becoming the villain known as Mr. Sinister. Dr. Xavier was also the physician of his wife Rebecca Essex. James spent many years chasing after his former friend, but Sinister was always steps ahead of him. Fearing he was getting too old, he prayed that someone would stop him for good.
- His objections to Charles Darwin's theories on Natural Selection seemed to be based on religious grounds.