Elemental HERO Neos, often shortened to Neos in the anime, is a character version of the card "Elemental HERO Neos". It appears as a Duel Spirit in the anime and a Single Duel opponent in a number of video games. His name is rendered Elemental Hero Neos in his earlier appearances.
Neos first appears in Jaden's Duel against Sartorius, telling him to fight the light, with darkness. Through most of the Duel, he guarded the keys to the mind control satellite from Sartorius. He later assisted in destroying said satellite with the help of Tyranno Hassleberry.
In the third season, Neos appears during the duel between Jaden and Jesse Anderson (Yubel) and later against Yubel again. Later, Jaden summoned Neos generally for help, he could do this with Yubel's powers.