Bau was a Chinese resident of London and the husband of Ru. (TV: Aliens of London)
He lived with Ru in 136 Enoch Tower. When Rose Tyler returned home safe on 5 March 2005 after the explosion at Henrik's, Ru and Bau knelt on the floor in front of Rose, holding their hands in prayer. (PROSE: Rose)
He accompanied Ru to Jackie Tyler's alien party. He looked through a serving hatch at the argument going on between Jackie, Rose Tyler and Mickey Smith. Mickey was trying to keep Rose's time travelling a secret, so when asking her to blab it out to Jackie, he shut the door — and the window — on Bau. (TV: Aliens of London)