As the series progressed, various other player characters have appeared, such as fellow Maverick Hunter Zero who was created by Dr. Wily of the Classic series, OVER-1, created jointly by Dr. Light and Dr. Cossack, and Axl, a Reploid with an adolescent personality who has the ability to shape-shift into other Reploids. Zero would later star in his own spin-off series, Mega Man Zero.
Like its previous installments of games, Mario Kart Wii incorporates playable characters from the Mario series, who participate in kart races on various race tracks using specialized items to hinder opponents or gain advantages. The game features multiple single-player and multiplayer game modes including a four person split screen. Online multiplayer via Nintendo Wi-Fi Connection was available at launch, but was discontinued in May 2014, along with other Wii and Nintendo DS games that supported online play. Many fans have created alternative servers to continue playing on, one of the more notable being Wiimmfi.
According to the in-game backstories, the world of Hyrule was created by the three golden goddesses: Din, Farore, and Nayru. Before departing, the goddesses left a sacred artifact called the Triforce, which could grant powers to the user. It physically manifests itself as three golden triangles in which each embodies one of the goddesses' virtues: Power, Courage, and Wisdom. However, because the Triforce has no will of its own and it could not judge between good and evil, it would grant any wish indiscriminately. Because of this, it was placed within an alternate world called the "Sacred Realm" or the "Golden Land" until one worthy of its power and has balanced virtues of Power, Wisdom, and Courage in their heart could obtain it, in its entirety. If a person is not of a balanced heart, the triforce part that the user mostly believes in will stay with that person and the remainder will seek out others. In order to master and control the triforce as a whole, the user must get the other parts found in other individuals and bring them together to reunite them. The Sacred Realm can itself be affected by the heart of those who enters it: those who are pure will make it a paradise, while those who are evil will transform it into a dark realm.