Leo, short for Leonard, known as Lua in the Japanese version, sometimes romanized as Rua (see below), is Luna's twin brother, and was one of the Signers who possessed the Heart Mark of the Dragon (as well as the only other Signer aside from Yusei Fudo, who has been able to weaken the "Meklord Emperors"[6][7][8]). He and Luna aid Yusei, whom they admire and support, in his Duels. Leo is the older twin of the two and has a lively and blundering personality. He and his sister also have a vignette before each episode in the Dark Signers arc known as card of the week.