context: The film starts with a brief recollection of the "Killing Angel", a dangerous assassin that has been operating in most of southeast Asia. The Killing Angel has no known accomplices or colleagues, is not affiliated with any government, religious, or criminal organization, and to this date their true identity has still remained secret. The Killing Angel is believed to be responsible for 6 murders in the past year alone, with only one thing connecting each of the assassinations - all the victims were criminals and deserved to die.Then the movie quickly moves on to the Killing Angel's most recent killing, the well-publicized assassination of a notorious ex-yakuza crime boss. Working swiftly, the Killing Angel is able to overcome the criminal's defense systems, quickly incapacitating the boss's bodyguards and isolating his target. In a fit of desperation, the crime boss promises to triple whatever fee the Killing Angel is being paid to kill him, then goes on to warn the vigilante that there is a massive revenge fund set to avenge his killing. Ignoring his pleas, the Killing Angel silently kills the crime boss.The scene then switches over to the story of Fu (Jet Li), a small-town gang member who lives an extremely simple and modest lifestyle, albeit being a contract killer. It is revealed that Fu is very kind and has trouble killing innocent people, a trait that causes him to be disliked by the other low-rent triad members. When Fu's boss reveals that there is now a $100 million US bounty on the Killing Angel's head for the slaying of the yakuza boss, Fu is quick to volunteer for the job, but is instead insulted.Fu then attempts to enter the building where the crime boss's lawyers are discussing the terms for the revenge fund, but is detained at the entrance and ushered out by security guards. In a surprisingly quick sequence, Fu defends himself by rapidly incapacitating each of the guards. His lightning-swift martial arts skills draw the attention of Ngok Lo, played by Eric Tsang, a seedy contract booker and loan shark, who comes to Fu's aid by pretending that he is an agent and Fu is his actor. Thanks to Lo's smooth talking, the pair is able to sidle into the meeting.The meeting however, comes to a halt when government agents, led by detective Chan (Simon Yam), raid the building in search of known criminals who are meeting there. Chan, a leading detective, has been working tirelessly to expose the Killing Angel's true identity for years. The movie then switches over to another sequence, where the character of Eiji Tsukamoto, the slain crime boss's grandson, played by Renji Sato, is introduced. Tsukamoto, fed up with his grandfather's cowardice in life, now seeks his grandfather's power in death. Tsukamoto consumes a portion of his grandfather's cremated ashes, an act that causes the deceased lord's top aid to call him insane, but now all of the family's agents and gang members serve Tsukamoto as their new master.Fu and Lo get to know each other - Fu is an ex-soldier from mainland China, part of a special, world-famous unit known as the "Golden Soldiers". When Lo asks for a demonstration of Fu's skills, he is able to rapidly take down several ruffians simultaneously, but falters when he is confronted by a woman. Lo then explains the deal with Fu, and they head for an amusement park to assassinate the first person believed to be the Killing Angel. However, when they get there, it is revealed their target is a simple family man, and instead of killing him, Fu saves his life by killing his other assassins, the low-rank triad members he formerly lived with.Fu and Lo are then arrested, but they are bailed out by Lo's daughter, Kiki (Gigi Leung), an intelligent and successful lawyer fed up with her father's scandalous ways and criminal connections. Fu moves in with Lo now that he has no place to stay, and they quickly become friends, Lo claiming he used to be an infamous hitman known as the "Killing Tank" but proving he has no real combat skills or experience.The next day, Fu and Lo travel to a nursing home, in search of an old acquaintance of Lo's known only as "Uncle Leung". Unbeknownst to them however, Tsukamoto's agents have already traveled to Leung's home. While searching his apartment, a third assassin arrives, an explosives expert. The three parties have a standstill in the hallway when Uncle Leung suddenly appears. Chaos erupts as the explosives assassin blows up the apartment, and Fu and Lo immediately take Leung and start running, pursued by both the grenade-using assassin and Tsukamoto's agents. Eventually Fu and Lo are confronted by the third assassin, and he tries to kill Leung with a hand grenade, but Fu kicks the grenade back blowing up the assassin with his own grenade. Before they can escape, however, they run into Tsukamoto's lead bodyguard, known only as "the Tall Guy" (Raul Rapovski), who is guarding the entrance. The Tall Guy and Fu have a battle, where Fu gains the upper hand before the Tall Guy uses light-emitting devices worn on his fingers and shoes to blind Fu and beat him down. With Fu defeated, the three are quickly surrounded by the rest of Tsukamoto's agents, as well as Tsukamoto himself. Desperate, Lo quickly shakes Uncle Leung, telling him to tell the others Lo's innocent, but the old man emits only one word, a Cantonese obscenity, before he dies. Frustrated, Tsukamoto shoots the dead Leung in the head before turning his gun to Lo, but the Tall Guy says to leave them, advising that killing innocents will only attract more unwanted attention, and Tsukamoto and his agents leave.Back at Lo's apartment, the two are alive, but visibly shaken. Kiki and her fiancee, David, then arrive, to finish moving out Kiki's belongings, as she is moving in with David. Noticing Fu and Lo's battle-scarred appearances, Kiki takes Fu to an ice rink, questioning him as to what her father is up to again, but eventually warming up to him and the two become fast friends. When Fu returns to the apartment, Lo explains his story, and why he was searching for Uncle Leung.A few years prior, Lo had met Leung at an antique shop, where the old man had been attempting to sell some war notes. Feeling pity for the elderly man, Lo befriended him, and learned that the old man's entire family had been slain by a Japanese criminal. Since the notes were in truth worth a lot of money due to their historical significance, Lo told Leung to keep them, and only cash them in in the event that this Japanese criminal is killed. Unknown to Lo, this criminal was actually Tsukamoto's grandfather, and when he was assassinated by the Killing Angel, Leung really did cash in his notes and forward the money to Lo. Now there is a paper trail leading to Lo as the Killing Angel, which is why he was trying to find the old man and exonerate himself.As they are watching the television, there is suddenly a news report of an apartment fire. Lo is visibly shocked, and when questioned, he reveals that the inflamed apartment was actually where Lo lived a few years back. Before the two can escape, however, the power goes out. A sub-machine gun wielding hitman then breaks into the apartment, using his gun and his night vision goggles to track the two down. Fu manages to kill the assassin by kicking him out of a window, and the two leave the apartment, only to be confronted by even more hitmen in the elevator shaft. The two finally manage to escape, and discuss their further plans.The pair make a quick stop at Kiki's engagement party, where Lo apologizes to Kiki for being a bad father, and in advance for what he is about to do. The two are also confronted by detective Chan, and Fu guesses that Chan is actually the real Killing Angel, and Chan admits it. Fu remarks that he could kill Chan instantly and win the $100 million US bounty, but Chan replies accurately that Fu is not that kind of person, and should not be a hitman.Fu and Lo then arrive at Tsukamoto's complex, where Lo admits to being the Killing Angel, and Fu then pretends to shoot him. However, it is revealed that the revenge fund's lead lawyer has arranged a deal with Tsukamoto, so that no matter who kills the Killing Angel, it will be Tsukamoto who gets the bounty. The two are in trouble as Tsukamoto's agents close in, but then the real Killing Angel, detective Chan, arrives, and starts killing the gang members. After an extended series of fight sequences, Fu manages to kill Tsukamoto, the Tall Guy, and all of Tsukamoto's bodyguards and henchmen.As an ending to the movie, there is one last scene where all the survivors gather for a business meeting. Arranged by the revenge fund's lawyer, the bounty has been split between Fu, Chan, and Lo. Fu and Chan then have a conversation, where Chan states that he is getting too old for the business, and is going to give up the mantle of the Killing Angel. He wants Fu to become the new Killing Angel, recognizing not only his skills but also his inability to hurt the innocent and exact justice on evil. Fu's reply ambiguous, the credits roll.
question: Who is Lo's daughter?
answer: Kiki