So I'm writing a musical comedy about a serial killer who falls in love with someone who he originally intended to kill. I'd quite like it to have a happy ending because it's obviously quite dark material and I want to try and keep it as light as is possibly possible. My question is, how can I redeem a character who prior to the story has killed possibly hundreds of women for fun. Obviously, morally, it's unlikely that he could ever be truly redeemed, but I want the audience to be able to like him in spite of his murderous ways. I don't want him to have to deal with shed loads of guilt either as that would really put a downer on the whole thing and it's meant to be a comedy,
have you read rain fall by barry eisler ... okay its not a musical, but the plot is relatively similar (John Rain, Assassin falls in love with a woman hes supposed to kill after killing numerous other people including her father... goes to war with the yakusa to save her, loses her at the end when she find out he was behind her fathers death)
Reminds me of "Wild Target." A charming comedy with Bill Nighy, Emily Blunt and Rupert Grint. Assassin falls in love with woman he is supposed to kill. Worth watching. I'm a bit skeptical of making a serial killer sympathetic to readers... bit of a difference between being paid to eliminate individuals according to an organisation's strategic goals, and an individual choosing to extinguish life purely for sick enjoyment. The idea of a murderer falling in love with an intended victim borders on creepy AF and would be a hard sell to the audience. I don't really have any tips to accomplish that. But you should watch Wild Target.
Another voice saying that assassin would work better than thrill-kill murderer. There's something wrong with both, but at least there's a discernible motive for the first. Serial killers are pretty unredeemable.
A comedy about a serial killer that kills women for fun? I'm all for dark humour, but good luck with that one.
As others said, the only way this would work is if the killer were either a paid assassin or a self-appointed vigilante. At least they have grounded reasons and can plausibly be convinced to lay down their guns/knives and get on the right path. A sick serial killer who takes pleasure in hunting down and murdering women? I'm not sure how you can make him redeemable. :/ Good luck, though.
But it's not a romantic comedy. I'd like to read that, actually. All the puns with "I love you so much I could eat you", etc. I've been thinking about it and maybe it's not impossible to do. Will take genius. Maybe not a romantic comedy, which is implied in the OP, just dark humour.
Cue the serial killer with a conscience, his victims all researched (as serial killers do) and found to be terminally ill or manic to suicidal (thus keeping it light). Mercy killings, his indulgences only slightly compromised; their salvation a certainty. A 'win win' modus operandi for our plucky protag.. Yes. Nice looking Dean Winchester type with accompanying charm. Yes do it.
Perhaps if the people he murdered are were more horrific and criminal than him it could work. I'd tend to hate a serial killer a little less if he was killing other murderers, racists etc.
Why redeem the serial killer? Why not have him groom her into his own little sociopath? I could get a kick out of that in a dark homour comedy. While there are a lot of people denouncing the relationship, Joker & Harley Quinn are an insanely popular and loved couple. No, it's not meant to be romanticized per se as an ideal to emulate—but it's wonderful in so much as her crazy matches his crazy. They are both psychopaths (she might be a sociopath, depending on origin version) and both are ruthless killers with no moral compass. That's fun. There's a cathartic element when characters have no inhibitions or restraints in some way. Say what they want. Do what they want. Just 'cause they want. And everyone to some level wishes they were like that, with no thought to repercussions or societal perception. I also love the film Mr. Right with Anna Kendrick. It has an ex hitman who sorta grew a morality that "murder is wrong" so logically murders everyone who contracts him for a hit on someone else. He falls in love with a goofy girl who finally freaks when she finds out he meant it when he was saying he was killing people (she thought he was joking). He tried to save her from the baddies who're after him but he's avoiding killing now for her sake so she won't freak out, so you think it's going the redemption direction, but instead she actually cracks and just kills the two main villain guys holding her hostage herself, and the ending is they both are reverse hitmen or something happily together. It might be my favourite romantic comedy ever. Honestly, instead of redeeming him it would be great if she had something worthy of psycho all along that their relationship just brought out. Make them an adorable killer couple. Handled well (which any direction you take this would have to be, considering the material) it could be dark but entertaining and funny. That's my two quarters, at any rate
I like NoGoodNobu's take! A Joker and Harley-esque. Joker and Harley relationship would be fun to see play out. If his killings were fun and nonchalant, if they were handled like in a cartoon (think Sideshow Bob) then I could dig it.
The good news is that most serial killers are sociopaths, and guilt isn't really in the cards for them. Because it is a comedy, as long as you work the "dark comedy" aspect of it, and find a way to make him likeable for the audience, they will let him slide. Options: 1.) Make the character completely unaware of the impact of their actions. Make their indifference to others a "gag." Even though it is only a so-so show, the TV show Santa Clarita Diet has a character that has to kill people occasionally, but doesn't seem to have a problem with it. You can use that as a starting point. 2.) Make them a wise-cracking slasher with a screw loose. Think Dead Pool. People will forgive murder if you make them laugh. 3.) A Clockwork Orange is one of my favorite books. The protagonist is as close to a sociopath as you can realistically get without making him a monster. In the original British version, the character has an epiphany and sees a way to turn his life around. He wants to change. Not out of remorse, but just out of growth.
Have you ever read Red Dragon by Thomas Harris? It does not match the tone it sounds like you are going for but there is an interesting part where the serial killer (nicknamed The Tooth Fairy) tries to fight back against the delusion that compels him to kill. He fails but it's a part of the book had me rooting for the killer. Could be worth a look.