He is later tricked into allowing Xehanort's Heartless, Ansem, to possess his body.
Following Ansem's defeat, Riku helps Sora and King Mickey close the door to Kingdom Hearts, remaining on the other side with the king.
In Chain of Memories, Di Z helps Riku escape from the dark realm.
Initially rejecting his darkness out of guilt for his betrayal, Riku resolves to wield both powers of light and darkness to battle Ansem, whose essence lingers in his heart.
Riku is also briefly playable at several points in the "Dark World" in Kingdom Hearts III.
His signature weapon is the "Soul Eater" sword, a manifestation of the darkness in his heart.Various types of merchandise modeled after the characters' likeness have been produced, including figurines and jewelry.The characters have garnered praise from several video game websites and magazines for the quality of their voice acting and visual style.Comments have focused on the accurate presentation of Disney characters, the unique visual style of Square Enix characters, how well all the characters blend together, and the consistent quality performances from voice actors.The Kingdom Hearts series is directed by Tetsuya Nomura, the character designer of the games.The series centers on Sora's search for his friends and his encounters with various Disney and Final Fantasy characters along the way.Players primarily control Sora, though there are numerous characters that join Sora's party as computer controlled members.Nomura has stated that Riku's name can be interpreted as "land", since the on'yomi pronunciation of Japanese word for "land" is riku is the initial player-controlled character of Kingdom Hearts II, featured during the game's prologue segment.Introduced as a youth living in a virtual simulation of Twilight Town, he discovers himself to be Sora's Nobody, born when Sora transformed into a Heartless to restore Kairi's heart during the events of the first game.When his world is beset by creatures of darkness known as the Heartless, Sora comes into possession of a weapon of light called the Keyblade, Originally appearing as a non-playable character in the original game, where he is introduced as 15 years old, he has a playable role in the "Reverse/Rebirth" story mode of Chain of Memories, the multiplayer mode of 358/2 Days, and the core story of Dream Drop Distance.He is also a computer-controlled party member exclusive to the final level of Kingdom Hearts II, and is temporarily playable during a sequence where Sora is incapacitated in the game's final boss battle.