Harrington Rosewood, known as Mitsuru Ayanokoji (綾小路 ミツル, Ayanokōji Mitsuru) in the Japanese version, is an Obelisk Blue student who is head of Duel Academy's tennis team, as well as the heir to Ayanokoji Motors. He fell in love with Alexis Rhodes at first sight and desires to date her, much to the jealousy of Jasmine and Mindy. After seeing Alexis being friendly with Jaden Yuki, he grows jealous and duels Jaden over who becomes Alexis' fiancée. He loses the Duel. In the dub, he vows to always love Alexis while watching the sunset. In the original version, he yells that he hates Dueling.
Harrington uses a Tennis Deck, which largely includes "Ace" cards that inflict effect damage to his opponents, and "Ball" monsters like "Mystical Shine Ball" and "Mega Thunderball". His signature card, "Deuce", causes the Duel to resemble a tennis match by restricting the amount of times an opponent can attack, and giving the victory to the first Duelist to inflict damage twice.
