Shido Gecko

Shido Gecko is Adrian's younger brother. An innocent soul, he is the biological heir to the Gecko family and serves as a roadblock to Adrian's quest for power. Several years after Adrian is taken in by the Gecko family, Shido is born as the rightful heir to the Gecko family. Because he is the biological heir, Adrian is looked down upon. Jealous of his brother, Adrian attempts to kill him, but decides to support his sibling instead. Later in life, Shido is plagued with an ailment, but is cured successfully by Adrian, who is now obligated to serve him.