Ike is the main character in Fire Emblem: Path of Radiance. He also plays a very prominent role in Fire Emblem: Radiant Dawn, where he is also a playable character.
Unllike most Fire Emblem lords, Ike is not a descendant of a royal family. Instead, he is the son of a common family as seen by his clothes (no crests, beat up clothing). For the most part of the story in Fire Emblem: Path of Radiance, he is in the service of Princess Elincia. Ike is nice and rather naive, but grows into a brave character later on. He has little memory of his life in Gallia as a young kid, and prior to joining the Greil Mercenaries, shows that he does not know the Laguz. He is very protective of his friends and family. His motivation for most of the game is to avenge his father's death, but he seeks no reward in aiding Crimea's liberation and helping Elincia to claim the throne as queen, except for the usual payment as being a mercenary. Although he has no desire to become a noble, he accepts the title as Lord so he can lead the Crimea Liberation Army after his triumph over Oliver.
Ike is the son of Greil, leader of the Greil Mercenaries, and takes leadership when his father is killed by the Black Knight. Ike is first presented as the newest member of the Greil Mercenaries. The other members look down on him as a rookie, such as Boyd and Shinon. After learning about Daein's invasion, Greil makes Ike work harder to prepare him for the task of leadership. Following Greil's death, Ike takes over leadership of the Greil Mercenaries, to Gatrie and Shinon's disdain. After Shinon telling Titania that he would not serve Ike, Titania got mad at Shinon due to her affection towards the now departed Greil. Gatrie left alongside Shinon because he felt his skills deserved a better challenge, but rejoined Ike at Astrid's urging in Chapter 13 because of his love for the mercenary group.
After remaining in Gallia, and realizing that Caineghis is unable to help him, Ike leaves and is escorted to Port Toha by a squad of Laguz including Ranulf, Lethe and Mordecai. Ike then leaves and travels around the continent, meeting and recruiting many people along the way.
Ike, the hero of the Mad King's War, returns in Fire Emblem: Radiant Dawn, as a main character. He starts as a Hero class, and wields the sword Ettard, but later reacquires the divine blade Ragnell, which he had previously used while dueling with the Black Knight in Path of Radiance, but subsequently turned it over to Begnion when Sanaki declared it a sacred treasure. In Part IV of Radiant Dawn, Ike becomes a Vanguard with the blessing of the goddess Yune and finally avenges his father's death and defeats the Black Knight in a one-on-one duel. Upon the Black Knight's defeat, Ike then takes possession of Alondite, the Black Knight's personal blade and Ragnell's counterpart.
It is also revealed that he witnessed Greil killing Elena due to the medallion's chaos energy, but his memory is sealed by Sephiran to prevent the painful truth. Once the goddess Ashera is defeated and all the countries are made stable, Ike travels to another land and leaves the continent of Tellius behind forever.
Super Smash Bros. Brawl
In Super Smash Bros. Brawl, Ike is the new Fire Emblem character, said to replace the former Fire Emblem extra Roy. Unlike Roy, Ike has moves mostly different from Marth. Ike has strength and range. Despite these aspects, he also has a poor recovery: he can either go only vertical or horizontal, and his recovery is easy to block. Currently, Ike is in the D Tier, far below Marth.
Two aspects from Roy were brought over to Ike in the game. For one, his Standard Special Move, "Blazer," can overcharge and release a powerful explosion but gives 10 to Ike, just like Roy. Secondly, Ike has a stronger Counter than Marth, although Roy's multiplied damage by 1.5 and Ike is only 1.2, but regardless, is more than what Marth has.
Ike has a Final Smash called "Great Aether," a move which fans say might be based on his final blow to Ashera in Fire Emblem: Radiant Dawn using Yune's power with his traditional Aether.