Sultan Giyaseddin

Sultan/Şehzade Gıyaseddın Keyhüsrev was the eldest son of Sultan Alaeddin and Mahperi hatun.

First appearing in season 4, the prince is shown hunting with his father, which is a distraction for the sultan to decide who his heir would be. However, the young prince's hopes of being sultan are destroyed when the Sultan informs him that Gıyaseddın's younger half-brother, Kılıçarslan, will inherit the title. His grief is shown as he digs his thumb into an arrow by his side.

Nevertheless, Giyaseddin accepts this, and forgets his eagerness. His mother, although, refuses to let Kiric Arslan be the sultan, and begins to scheme with Saddettin Kopek. Soon, the prince learns of this and firmly instructs Mahperi to stop, saying that his half-brother is his family too.

Later on, the Sultan dies in his son's arms. Giyassedin suspects Ertugrul as he was with him, and almost kills Ertugrul if not for Ibn Arabi.

He soon befriends Ertugrul as he could not trust anyone else, and Ertugrul guides his way. When Mahperi orders Şehzade İzzettin Kılıçarslan and his mother to be executed, Giyaseddin is deeply saddened. He immediately takes up the position of sultan, and tries to fix what his mother had ruined.