As his name implies, William is notorious for being a weeaboo. He gets extremely upset when people criticise anything about animes and other media originating from Japan. He once screamed extremely loudly and burst into tears when Horry Henry spat on his sushi at school in Big Fat Trouble in Little Bashtoun. His bedroom is filled with J-pop CDs and anime soundtracks, and it is revealed in Horry Henry's Scooter that he owns a total of 42 bodypillows based on anime girls. He is also rumoured to have a large harem of waifus.
- His top 5 favourite anime (as supplied by WatchMojo.com) includes Fairy Tail, Naruto, One Piece (not the 4Kids dub), Lucky Star, and Love Live!.