As well, their names in the Japanese version are 'Hikari no Kamen' (Mask of Light) and 'Yami no Kamen' (Mask of Darkness)

They duel Yugi and Seto Kaiba twice. The first duel was fought in an alley, and Kaiba and Yugi won the duel in very few turns. The second was fought on top of a 50-floor skyscraper. It was to be a 2 vs. 2 duel. Once any player's life points hit zero the surface they were standing on would break and send that duelist on a 50 storey plungs to the bottom floor. (In the 4kids dub, it is explained they would fall to the shadow realm.) During the first half of the duel, Lumis and Umbra had the advantage. The reason for this was simple: Kaiba refused to work with Yugi. In the end, Kaiba summoned Obelisk the Tormentor and attacked Umbra. Umbra got caught on a flag pole instead of going to the shadow realm. Lumis was not so lucky. Marik, who was very angry (understandably), used his Millenium Rod to take over Lumis's mind and told Yugi that his friends were now his mind-slaves.