Who should I kill?

Right now, I'm plotting a fantasy story idea that I may or may not write (I really would like to write it though). My problem is I know one of my MCs is going to die. Their death will differ depending on the person so I don't know how they will die but I know in my heart someone will die. I have 5 candidates to choose from and can't pick.

Miles- A human farmer boy from a mixed town i.e. half-breeds, elves, humans. His family became poor after paying for Miles' five elder brothers' wives (It's their culture. It's like bidding). He's really close with his next door neighbours excluding Lunek, their son. His neighbour's little girl is like a sister to him so when she's kidnapped, he's the one that starts the investigation. Children were going missing a lot. He learns sword fighting from Lunek during the investigation.
He's not intelligent but he's strong and hard-working. He's very determined and can't stand time wasters.
He's the love interest of Celestia.
(He isn't as developed as some of the others yet)

Lunek- A half-breed elf from Miles' town. His little sister was kidnapped and when he finds out that Miles is going to investigate, he joins him. Miles and Lunek have a little argument about it but Miles gives in. He's fierce protective of his little sister. Lunek is very handsome and a bit of a ladies' man.
He's the opposite of Miles which is why they don't get along. He's street smart and lazy. He's skilled with a sword. He's a good guy if you look deep enough.
He's the love interest of Nixie
(Again, he isn't that developed)
The reason I don't want him to die is because I think Nixie needs someone that actually loves her. I don't think she'd be able to recover from his death.

Georgia "Georgie"- A shape-shifting human from Miles' town. She is Miles' best friend and believes herself to be in love with him. Shape-shifters are random in this world. She lacks training so she can only transform into things she's really familiar with. She has two younger siblings, a brother and sister, and worries that they will go missing too if she doesn't do something.
Shape-shifters aren't seen as desirable because, in their mythology, they're fickle, wild, jealous and dangerous. In reality, she can be jealous and she could be dangerous because of her abilities but she isn't fickle or wild. She is bubbly which contrasts Miles' serious nature.
She doesn't have a love interest (If you don't count Miles).
The reason I don't want her to die is because it would feel too convenient. The other MCs get their love interests and the spare is killed off.

Celestia- An Elven Princess from an exclusively elf city (The last one in the land). Her mother died in childbirth. When she was twelve, she was attack by a ? (Any help?), that left a white scar of a claw on the right side of her face that dragged the corner of her eye down. She is blind in that eye. She was sent to study magic with one of the best wizards in the land for her protection. When she arrived home, she was forced to stay in the castle by her father.
Miles, Lunek and Georgia were greeted by the rather polite princess. Her curious nature causes her to overhear their conversation with her father. She hears about the plan and wants in. She wants to feel useful and wants to know what the world is like. She runs away with the group. She's a bit put off by sleeping outside and walking all day but is determined to not complain.
She is hot-headed, curious and genuinely cares about people. She is very useful to the group as she's the only one with magical abilities.
She is the love interest of Miles.

Nixie "Nix"- A half-breed mermaid from a fishing town. Like Celestia, she only has a father. Nixie's mother didn't die but she's never met her. There are no mermen, only mermaids. Mermaids can go to the surface once every ten years. During that visit, they mate with the humans. The offspring can choose to join their mothers or not. The mermaid mother is allowed to visit their daughter (Though some did have sons but they weren't wanted) on their eighteenth birthday see whether or not the offspring will join them. Nixie's the only half-breed mermaid in her village.
For a long time, Nixie had all the traits of a typical half-breed mermaid. She was flirtatious (Even when she didn't know what flirting was), charming and beautiful. She loved the attention. She had many boyfriends in her life but none actually loved her. The boys just found themselves going ga-ga at her beauty. She grew annoyed and when she received no marriage offers by the time she turned seventeen (They come of age at sixteen) she hid herself away. She chopped off her long golden locks and covered her head with a hat. She never made eye contact with anyone and barely spoke.
She's slightly distant with people and kind of frosty. She's forced into joining the group by certain circumstances. She is very skilled with a bow and arrow because she would travel to the forest and fetch something to eat that wasn't fish.
She's the love interest of Lunek.
I don't want her to die because I love her character so much and it would seem out of the blue for her to die. It would feel forced. I can't imagine her being killed.

Please help me! I'm so stuck! Sorry, it's so long.

hm... i'm thinking Celestia.
a) shes one of the few characters you didn't have a 'i dont want her/ him to die because...' note for
b) she seems like a pretty innocent character, so her death would make an impact with the reader, along with impacting the group of remaining characters
c) she seems like the kind of person to sacifice herself for the good of others (and this is me going off the paragraph you have about her)

hope this helps

If you really don't care, then roll a regular 6-sided die. 1= Miles, 2 = Lunek, and so on. If you roll 6, then two characters die: roll again until you have two different numbers. Another 6 = three characters die. (You probably ought to stop at three, though.)

Then sit down and actually write the story. By the time you get to the death scene, things may have changed completely, and you can then change your mind about who lives (or doesn't). But there won't be any story at all until you WRITE IT. Talking about it is nothing.

I would like to add that for plot purposes, you should not worry whether a character would be "hurt" by someone else's death. In fact, the more emotional conflict, the better -- that's what makes a story worth reading. Don't get so attached to your imaginary people that you don't want to hurt them. They do have to get hurt, and they have to feel it, or the story will be boring! People in stories have to face obstacles, fail at some of them, and grow or develop as a result. Otherwise their wins don't mean anything. Their victories must be earned. If the characters get to the end of the story and they haven't changed since the beginning (physically, mentally or emotionally), you have written either a classical tragedy or a very very bad drama.

By the way, can you explain the following questions:
- If shapechangers are known to exist, and they are already feared and disliked, why are they permitted to walk around unsupervised, with no special attention from the government? They have great potential as criminals or spies, so any king or noble with an ounce of brains is likely to want them identified and controlled in some fashion.

- what is an underage princess doing marching around with commoners, and no guards? Even if she did run away from home, why is her family allowing her to wander loose, instead of tracking her down and bringing her back? And why is the party putting up with a companion who probably has few practical skills and is likely to draw dangerous attention? There's a reason princesses in prosperous kingdoms are guarded at all times: they make great targets for kidnapping or assassination...

I vote for lunek , because it would be really sad if he went out to save his sister and ended up getting himself killed. Plus it might be a nice development for him, going from lazy ladies man to a person who gives his life for his sister. The mermaid as well, since she'd have to learn how to cope without him and find some self worth elsewhere

Does someone really have to die? I think it would be better if you have a better reason than because you felt like it.
Most people I know don't have friends who died young.
But if you really want to, my perspective is that it is popular to pick off the characters who are innocent or weak. Or they pick off the characters that are in the mentor status (I.e. person who gives out wise word, Brom from Eragon, Sirius from Harry Potter.) Or they pick off a lover and the characters can't be together. These are all cheap ways for drama. When I see it happens, it really doesn't affect me in any way. They only time I cried when I saw a mentor type character die was on Jet Li's Fearless. The MC went from bottom low to really changing his life and figuring out everything to do, then he was murdered.
I rarely seen an unstable character die, if they do, it's because they committed suicide, did drugs, or brought death upon themselves purposely.
I would think outside of the box with this if you do deaths.
Most of all, I think you should just write and not worry about picking someone to die. Many writer's tend to not focus on the person who is going to die, even if they are a MC. So sometimes I can see it way before it happens. Or the character doesn't get developed enough, so when death comes, it is a cop out for cheap drama.