Waluigi is Luigi's very tall and skinny rival and Wario's partner. Waluigi made his debut in Mario Tennis and since then, he has made playable appearances in many of the Mario series' spin-off titles. He has been voiced by Charles Martinet ever since his debut. His name is derived from the Japanese words, Warui and Ruīji, meaning "bad" and "Luigi". The details of Waluigi's past are unclear since he has no confirmed background, although he has evidently been antagonizing the Mario Bros., especially Luigi, for quite some time before his debut as seen in the opening of Mario Tennis, where he and Luigi confront each other.