Mr. Chau is the father of Knives Chau (why he decided to name his daughter Knives is a mystery) and the husband of Mrs. Chau. After his discovery that Knives was dating a white guy (although out of date), he went off on a rampage, hunting Scott down and trying to kill him with his antique samurai swords. Mr. Chau's full name is currently unknown.
Mr. Chau is first mentioned in Scott Pilgrim vs. the World, when Knives tells Scott that her father is nine years older than her mother.
Mr. Chau later appears as a mysterious figure in the first part of Scott Pilgrim Gets it Together, stalking Knives and Scott. Later on, he sees Scott and Kim Pine in the street and chases him, slicing straight through a streetcar in his pursuit. Cornered by Mr. Chau, Scott manages to escape through Subspace. Scott then sees Mr. Chau again on the way to work with Stephen Stills, but this time Scott manages to hide before he sees him. Stephen then reveals that Mr. Chau and his family sometimes dine at The Happy Avocado and once Mr. Chau even "incoherently thanked [Stephen]."
Later on, Scott ends up meeting Knives at Second Cup, and as he's about to leave he spots Mr. Chau outside. Knives reveals that he is her dad. She then explains that he must have gone on a rampage after he found out from her Auntie that she had dated a white boy. Mr. Chau sees Scott and, once again, gives chase. Scott travels through another Subspace door (into Ramona Flowers's head), this time, Mr. Chau follows, and ends up attacking Ramona. Scott, who is afraid of fighting Mr. Chau as he has a sword, runs into Ramona's apartment and (unintentionally) tricks Roxie Richter into fighting Mr. Chau, causing them both to fall off of Ramona's balcony into the back garden. Once Mr. Chau sees Scott man up and face Roxie, he gains respect for him, and ceases his cold-blooded vengeance.
Mr. Chau appears one last time, telling Knives in Chinese that Scott is a decent young man, and that her dating a white guy in the future may not be a bad idea after all. Knives, however, doesn't know what he's saying as she can't speak Chinese. Interestingly, the actual Chinese characters Mr. Chau speaks seem to be taken from a random piece of older Chinese literature, having nothing to do with Scott, dating, or even White Guys. It translates to: "And in Chinese, there are commonly a large number of measure words [a feature of Chinese grammar]. The clear differences in Northern Dialects are the types [of measure words] commonly used in Confucius's time, not regarding the surplus."
Mr. Chau possesses impressively powerful strength. He is able to slice straight through a streetcar cutting it clean in half (while holding his sword in only one hand, no less). He is also shown to have good stamina too as he manages to keep up with Scott whilst chasing him and effortlessly jumps off of Ramona's roof. Mr. Chau is also shown to be an excellent swordsman, being skilled enough to overpower Roxie and cause both himself and Roxie to fall off of Ramona's balcony during their small bout.
Mr. Chau is incredibly persistent in his goal of hunting down Scott. According to Knives, when he found out about her and Scott, his brain was split open and replaced by a purely mechanical engine of revenge. His unrelenting determination is shown when he effortlessly slices straight through a streetcar just to get to Scott, he also travelled through Subspace without any hesitation just to get at Scott. When he's not trying to mercilessly kill 23-year-olds, Mr. Chau's hobby appears to be collecting antique samurai swords.
Despite his apparent ruthlessness, Mr. Chau also has a sense of honor and forgiveness. When he sees Scott man up, battle, and defeat Roxie, he decides that Scott is a decent person and that it would be OK for his daughter to date a white boy.
In vs. the World
Mr. Chau is only mentioned in passing in Scott Pilgrim vs. the World, when Scott tries to explain why he and Knives should break up. Knives mentions that her father is nine years older than her mother.
In the game
Mr. Chau also makes a appearance in the Scott Pilgrim vs. the World: The Game as a hidden boss. He appears randomly on the world map. When you go to fight him, he will meet you on an open field. Mr. Chau is a very tough opponent, he is quick with his sword and can slash across the screen vertically and horizontally. You're given a very quick warning to get out of the way before he flies across the screen to strike. If you lose a life against him, the battle will end regardless of how many lives remain. Once he is beaten, he can be used as an assist character instead of Knives.
When summoned as a striker, Mr. Chau will teleport towards several enemies and strike them down with a powerful sword slash, usually defeating them with one hit, when finished, Mr. Chau will bow and teleport away. On occasion, his wife will be summoned instead.
- Given the fact that Volume 4 is set several months after Scott and Knives broke up, it's most likely that the "white boy" Knives' Auntie saw Knives with wasn't even Scott and Mr. Chau simply jumped to conclusions. Considering this, it's more likely that it was Young Neil that Knives' Auntie saw.
- Mr. Chau appears to have a soft side as he can be seen petting one of the rabbits that Roxie exploded into after her defeat.
- Although the Chaus are Chinese, he owns samurai swords, which are Japanese.
- When Mr. Chau eventually gives up on chasing Scott and goes back to Knives to tell her that she is free to date Scott in Chinese, the actual translation of his words is a commentary about Chinese language.
- To be exact, the message (when put into Google Translate) translates to the following: “And the obvious characteristics of northern dialects that usually have a large number of measure words in Chinese include the type used in the Confucian era, and the rest is irrelevant.”