"Do you find me sadistic? Y'know, I bet I could... fry an egg on your head right now, if I wanted to. Y'know, Kiddo, I'd like to believe that you're aware enough, even now, to know that there's... nothing sadistic in my actions. Maybe, towards those jokers... but not you. No, Kiddo, at this moment, this is me... at my most... masochistic." ― Bill's opening monologue to the Bride[source]
Bill, also known by his code-name Snake Charmer, was the titular main antagonist in Quentin Tarantino's Kill Bill series, particularly in the 2004 film Kill Bill: Volume 2. He is the founder and leader of the Deadly Viper Assassination Squad, the older brother of fellow assassin Budd, and the archenemy of the Bride (AKA Beatrix Kiddo); having murdered her fiancé and caused the premature death of her unborn child (or so she believes), Bill is the ultimate goal of the Bride's "roaring rampage of revenge.
He was portrayed by the late David Carradine.
Bill and his brother Budd never knew their father, instead growing up in the care of a pimp and part-time gang leader by the name of Esteban Vihaio; according to the Bride, Vihaio was just a friend of Bill's mother, though given his profession and the conspicuous anonymity of the father, it may be possible that he was also her employer. For much of Bill's childhood, Vihaio served as a father figure to him, lavishing attention on the young boy - and quickly discovering his legendary attraction to blondes; it's also likely that he also began his first forays into the criminal underworld while in Vihaio's care.
Eventually, Bill left home and traveled the world, acquiring more father figures and mentors along the way: one of them was the warrior and swordsmith Hattori Hanzō, who taught him the art of swordsmanship and even gave him one of the legendary Hanzō katanas; another was the near-mythical martial artist Pai Mei, who accepted him as a student despite his notorious disgust for Americans and Caucasians. Under the tutelage of the amiable swordsmith and the mysterious hermit, Bill honed his mind and body to deadly extremes, and though Pai Mei's famous Five-Point-Palm Exploding Heart Technique eluded him, he emerged from his education as a force to be reckoned with.
However, instead of parlaying his skills into a career as a warrior, Bill instead chose to make a name for himself as a professional assassin: it's not known how long he spent as a solo killer, but it's believed that he served as a hitman for the Tokyo Yakuza for a time, and even participated in the murder of O-Ren Ishii's parents (though it's never stated out loud, the hitman scene in O-Ren's flashback wears similar rings and possesses similar skills). Eventually, Bill's criminal activities brought dishonor to the name of Hattori Hanzō, and the swordsmith retired to become a sushi chef in Okinawa, determined never to make another sword again.
Eventually, Bill ended his days as a lone assassin by forming a dedicated group of contract killers known as the Deadly Viper Assassination Squad: consisting of Bill, Budd, Beatrix Kiddo, Elle Driver, Vernita Green and O-Ren Ishii, the group remained profitable and efficient throughout its years in operation. He also served as a mentor to a number of the assassins, including O-Ren, her associate Sofie Fatale, and Beatrix: out of all of them, he came to appreciate Beatrix the most, teaching her to improve her skills tenfold, even guiding her into the tutelage of Pai Mei, where - unknown to Bill - she became the first of his students to learn the Five-Point-Palm Exploding Heart Technique. Eventually, despite the age difference between the two assassins, Bill and Beatrix fell in love and started a committed sexual relationship.
The Massacre At El Paso
Some time prior to the events of the films, Beatrix discovered that she was pregnant with Bill's child, and realized that she couldn't allow her baby to be drawn into the violent lifestyle she and the other members of DeVAS enjoyed. So, despite sincerely loving Bill, she abandoned her current mission and vanished from the spotlight, allowing her friends to believe that she'd been killed in action. Bill was heartbroken, and spent a number of months looking for Beatrix's "killers" in a desperate search for revenge; unfortunately, though she'd done her best to cover her tracks, Bill was still able to pick up Beatrix's trail and follow it all the way to El Paso, Texas, where his ex-lover had settled down and gotten engaged to a rather mundane young man by the name of Tommy Plympton.
By the time Bill caught up with Beatrix, she was heavily pregnant and right in the middle of a wedding rehearsal; already shocked to discover that the woman he loved was still alive, the sight of her pregnancy and imminent marriage left him distraught, though he was careful to disguise his feelings on the matter. Bill remained perfectly courteous throughout his visit, never raising his voice when speaking with Beatrix, amiably introducing himself to the groom - not even getting angry when Beatrix decided to pass him off as her father.
Inwardly, however, Bill was enraged: seconds later, he called in the rest of DeVAS and had them kill almost everyone in the chapel, riddling the gathered family members and clergy with automatic gunfire; then, as the head of the group looked on, the four assassins pummeled Beatrix to within an inch of her life, leaving her a bloody mess. Finally, Bill offered his last farewells to his ex-lover, before putting a gun to her head; Beatrix had just enough time to explain that she was pregnant with his baby, before Bill shot her.
In spite of her injuries, Beatrix actually survived, though the gunshot to the head left her in a coma. It was during this particular coma that she finally gave birth; having taken Beatrix's final words to heart, Bill decided to raise her daughter as his own, eventually nicknaming her "BB." At some point, he also sent Elle Driver to poison the still-comatose Beatrix, but at the last minute he called off the mission and allowed her to live, claiming that she deserved better.
With Bill preoccupied with raising a child, the Deadly Viper Assassination Squad gradually drifted apart: Budd had a falling-out with his brother and retired to become a bouncer in El Paso; Vernita retired, got married and had a child of her own; O-Ren and Sophie returned to Japan and took over Tokyo's Yakuza, apparently with some support from Bill; Elle apparently continued her career as an assassin, remaining in contact with Bill - possibly enjoying a relationship of her own with him.
Finding the Bride
Bill spends much of the film both figuratively and literally in the shadows: even in flashbacks to the massacre or its aftermath, his face is never seen at all. He presumably spends much of the present day raising BB, only occasionally emerging from retirement to investigate Beatrix's activities: he's not surprised when his ex-lover awakens from her coma, nor is he surprised when she sets out to take vengeance on the members of DeVAS - including him. Even her acquisition of a Hattori Hanzō sword isn't that great of a shock to the jaded assassin: all the Bride had to do in order to force Hanzō out of retirement was to drop Bill's name.
Following the deaths of O-Ren and her cohorts, he interviews Sofie Fatale, now missing both her arms: he forgives her for confessing to Beatrix under torture, and mourns the damage that was done to her, but nonetheless allows her to convey the message that the Bride had ordered her to deliver. However, he was also careful to ask if Beatrix knew if her daughter was still alive (she didn't).
In the second film, Bill's face is seen for the first time in a flashback to the wedding massacre; in sharp contrast to his appearances in the previous installment, he remains in full view at all times. Chronologically, he first appears in the film during a meeting with Budd shortly after the deaths of O-Ren and Vernita Green: despite the long-standing disagreement between the two brothers, Bill warns him that Beatrix will almost certainly be after him next, encouraging him to hone his swordfighting skills. To his astonishment, Budd has sold his own priceless Hattori Hanzō sword for barely a hundred dollars (a lie: Budd's keeping it in his RV) and has no overwhelming interest in preserving his life - reasoning that Beatrix deserves her revenge. Nonetheless, Budd comes closer than any of DeVAS to killing Beatrix, shooting her in the chest and burying her alive - an execution she only escapes thanks to the techniques she learned from Pai Mei at Bill's behest.
In the meantime, Elle Driver murders Budd with a Black Mamba; when discussing it on the phone with Bill, she blames the death on Beatrix, claiming to have buried the Bride alive herself out of revenge. Moments after hanging up, however, she is confronted by Beatrix herself - who wins the ensuing brawl by ripping out Elle's remaining eye and leaving her in the trailer with the freed Black Mamba. With no other targets left, the Bride journeys to Acuna, Mexico, where she meets up with the now-retired Esteban Vihaio, who reveals Bill's location with very little prompting - reasoning that's the only way that his adopted son will ever be able to see Beatrix again. With the coordinates in hand, Beatrix seeks out his luxurious hacienda and enters without opposition - only to find herself face to face with Bill and their four-year-old daughter.
Final Showdown and Death
Astonished to discover that her child is alive, Beatrix spends the next few hours postponing her vengeance against Bill while the three of them enjoy a surprisingly pleasant evening together, complete with dinner and a movie. Eventually, the Bride puts BB to bed and confronts Bill: shooting Beatrix in the knee with a dart of home-made truth serum, Bill reminds her of her violent ways and how futile it would have been to give it up; shaken by her ex-lover's words, Beatrix confesses the events that led her to abandon him, and though she admits that she broke Bill's heart, she points out that BB should have had the chance to grow up without getting entangled in the lifestyles of her parents - and that running away from DeVAS was the only way to assure this. Both Beatrix and Bill end the conversation emotionally distraught, acknowledging that they have both done wrong against the other, and that the only way to resolve their enmity is in a duel to the death. After a brief swordfight in Bill's yard, the Bride is able to disarm Bill and perform the Five-Point-Palm Exploding Heart Technique on him: knowing the specifics of this technique, Bill quickly realizes that he's going to die. In spite of herself, Beatrix finds herself crying at the sight of this, prompting the two lovers to share one last heartfelt discussion, before Bill bids his final farewells, rises from his seat, buttons his coat and takes the five fatal steps into the darkness of his backyard. On the fifth step, his heart explodes inside his chest, and Bill collapses to the grass, dead.
With Bill's death, Beatrix's vendetta is complete, and she is able to raise BB in peace.
"We've done a lot of things to this lady. And if she ever wakes up, we'll do a whole lot more. But one thing we won't do is sneak into her room in the night like a filthy rat and kill her in her sleep. And the reason we won't do that thing is because... that thing would lower us" ― Bill to Elle Driver[source]
Bill is an immensely stoic individual at first glance, hiding his emotions and his motives from all observers; for most of the first film, he is little more than a voice in the shadows, demonstrating only cold, calculating responses to the problems at hand. Even his remorse over Sophie's mutilation sounds almost too quiet and understated to be real.
However, in Kill Bill: Volume 2, he shows a much more human side to his character in his past interactions with the Bride: during his fireside chat with Beatrix, he enthralls his lover with the tale of Pai Mei and offers her heartfelt warnings not to anger the cantankerous old master. Later, when they meet at El Paso, he visibly restrains his grief and anger over the Bride's sudden disappearance, never raising his voice - even putting on a jovial facade when the time comes to meet Tommy. Likewise, even when he finally loses his temper and orders the wedding massacre, he hides his emotions, attempting to end his relationship with the Bride on a friendly note even as he shoots her. Likewise, despite his strained relationship with Budd, he tries to save his brother's life by warning him not to underestimate Beatrix; when the Bride finally discovers Budd's Hattori Hanzō sword, she discovers it's been engraved with the words "To the only man I ever loved - Bill."
Towards the end, Bill's facade starts to unravel: genuinely friendly with Beatrix for most of the evening, his calm exterior gives way as the Bride finally admits the situation that led her to walk out on him, and Bill finally confesses the depths of grief and rage he felt at being abandoned. In the end, however, he accepts his death gracefully, acknowledging that he still loves Beatrix in spite of all her flaws, before willingly taking the final steps to his death.
- Martial Arts: As a pupil of Pai Mei, Bill was a highly-trained martial artist, and evidently held his own against the aged master upon delivering Beatrix for training - though not without sustaining a few bruises. His skills are displayed at length in deleted scenes from the film, where he is able to defeat the vengeful apprentice of one of his past victims - and his hired goons - in hand-to-hand combat.
- Swordsmanship: A master swordsman rivaling even Beatrix for sheer skill, Bill learned his art from Hattori Hanzō, and was able to conduct a brief but complicated swordfight without ever rising from his chair.
- Intelligence: Bill was highly intelligent, single-handedly coordinating and planning the operations of one of the most successful assassination teams in the world with ease, even lending his skill to O-Ren's takeover of Tokyo. In retirement, Bill amuses himself by formulating truth serums and other chemical concoctions; even over the course of a simple conversation, he proves sophisticated and insightful enough to deconstruct the Bride's motivations and plans in life.
- Handguns: He frequently used handguns on his targets and demonstrated a lightning-quick draw with his revolver and precise aim with his truth-serum pistol.
"As you know, l’m quite keen on comic books. Especially the ones about superheroes. I find the whole mythology surrounding superheroes fascinating. Take my favorite superhero, Superman. Not a great comic book, not particularly well-drawn, but the mythology. The mythology is not only great, it’s unique… Now, a staple of the superhero mythology is, there’s the superhero and there’s the alter ego. Batman is actually Bruce Wayne, Spider-Man is actually Peter Parker. When that character wakes up in the morning, he’s Peter Parker. He has to put on a costume to become Spider-Man. And it is in that characteristic Superman stands alone. Superman didn’t become Superman. Superman was born Superman. When Superman wakes up in the morning, he’s Superman. His alter ego is Clark Kent. His outfit with the big red “S”, that’s the blanket he was wrapped in as a baby when the Kent's found him. Those are his clothes. What Kent wears – the glasses, the business suit – that’s the costume. That’s the costume Superman wears to blend in with us. Clark Kent is how Superman views us. And what are the characteristics of Clark Kent? He’s weak, he’s unsure of himself, he’s a coward. Clark Kent is Superman’s critique on the whole human race. Sorta like Beatrix Kiddo and Mrs. Tommy Plympton... You would’ve worn the costume of Arlene Plympton. But you were born Beatrix Kiddo. And every morning when you woke up, you’d still be Beatrix Kiddo… I’m calling you a killer. A natural born killer. You always have been, and you always will be. Moving to El Paso, working in a used record store, goin’ to the movies with Tommy, clipping coupons. That’s you, trying to disguise yourself as a worker bee. That’s you tryin’ to blend in with the hive. But you’re not a worker bee. You’re a renegade killer bee. And no matter how much beer you drank or barbecue you ate or how fat your ass got, nothing in the world would ever change that…" ― Bill's infamous monologue and explanation of his motivation to Beatrix.[source]