Ike is the central character of Fire Emblem: Path of Radiance and one of the main characters in Fire Emblem: Radiant Dawn. He is the son of Greil and Elena, as well as the older brother of Mist. He is also the fearless leader of the Greil Mercenaries and the first and only main character who is not of noble birth.
In Fire Emblem Awakening, Ike makes another appearance as a DLC character, and is illustrated by Eiji Kaneda, the artist of Fire Emblem: The Binding Blade.
In Fire Emblem Fates, Ike comes along as an Amiibo unit; utilizing an NFC reader or a New 3DS he can be recruited by using an Ike amiibo.
(Source: Fire Emblem Wikia)