Dr. Alex Brisbane is a character appearing only in Yu-Gi-Oh! Capsule Monsters. He is the host of Alexander the Great's dark side.
He is a direct descendant of Alexander the Great like Atem, Seto, and Bandit King Bakura who they were actually direct ancestors of their modern-day counterparts. He was working with Dr. Solomon Muto in India exploring a mysterious pyramid. They entered it and only Brisbane got out, Dr. Muto apparently disappeared into thin air. Later, when Yugi and friends came, he led them to the chamber in the pyramid where Dr. Muto disappeared. It turns out that when professor Brisbane entered, he got possessed by the dark side of Alexander the Great and used Yugi and his friends to unleash the "ultimate power." Later, when the dark side of Alexander got destroyed by Yami Yugi and his friends, Brisbane was free, and Solomon explained what happened along the way home.