Okay basically big sis is alive. Since Sakuya was 6 and she looked 14-15 then, I'll assume that the sister is 7-9 years older.

1. Mom can't hold it back anymore. She takes the kids somewhere far away, a decent orphanage is the most royal legacy they could ever attain, before her death on the father's hands.

When Mom was killed, Sakuya cried so much. Sis acted fast and called police, leaving Sakuya stunned at how swiftly she handles things. "It's going to be all right, Sakuya."

2. But she cried overnight, which Sakuya listened to. Since then he swore to protect his one and only beloved. #AKA HE CAUGHT A YANDERE SISTER COMPLEX.

3. They grew up in the orphanage with a few troubles, and they were never adopted, but they could overcome it. Sakuya would always defend her sister if he could. He matured so quickly.

Once things settled, Sakuya's sister would be more laid back. She became bubbly and quite a jester, and she's rather of a pervert. She also doted on the little brother.

Sakuya was rather embarrassed, but he'd never do something that hurts her, like rejecting her. If sister-san tells him to die for her, even at a young age, he would.

4. In the canon! world, Sakuya was told to have a secret stash of 300 knifes. Well, he's gonna have that too.

Sakuya learned many martial arts and street fights, in case of Father wanting to revenge. It's clandestine from his sister, though.

5. He'd never trouble Oneechan with anything *mundane*. He also worked part-time, even if she forbids him. (when she was 20 and he was 13, they got out of the orphanage) Sakuya told her instead that she should focus on her college.

Studies, sports, martial arts, housework, he even did research on the father, and he had informations about each and every single boys (and even some girls) who tries to get close to his sister.

6. He never actually tried to hide his love to her, except for the fact that he's a tsundere, a heavy one. Even if he wasn't a cuddler, his Nee-san is free to do anything on him, resulting his odd hair, for one.

Sakuya will spend his allowance on her, buying things for her, get better food.

7. He doesn't only become a top student, he was a valedictorian even when he skipped a grade, and he's got scholarship. Polar opposite to Oneechan, who's only a smart student but has many friends, he was cold, like from before he met Mahiru. I'm pretty sure he's no friends.

8. "You're not gonna go on with this." His sister sighed, exasperated. "I want you to make friends, Sakuya. And I won't accept a no." She asserted.

"Why should I? I don't need more people that would betray me. I only need you, neechan. And I've got *insert 3-4 random names as kids from the orphanage*." Sakuya answered unhesitatingly.

"Sakuya"

Don't ask me how but sister managed to convince him to be more social. It was after they moved, because sister needs to work somewhere better, and Sakuya would go anywhere with his sister. Plus he can use his scholarship anywhere. Sakuya's checklist is study and job before love&friendship, even if his sister disagrees.

8. That's how he met Mahiru. He didn't know what to do at first. He'd never had good friends. There's a little- scratch that. Sister helps him with all and can you just imagine that red face when he was consulting with her.

"Oneechan" Sakuya inhaled, his head looking down. "What-what to do... with a friend?"

Cue the "MY LITTLE BROTHER IS SO CUTE BLESS-" Eventually, he gets to know Ryusei and Koyuki, becomes the class's clown, etc.

Mahiru is the only one he'd trust with his sister. And simple boi knows better than to say, "your sis is pretty."

Mahiru and Sakuya would have many things in common, resulting them being best friends. Sakuya won't have his headphones either.

9. (( SAKUMAHI CONTENT ))
He had another talk. "What to do when you fall in-"

"-It's Mahiru isn't it."

"..." Sakuya said nothing, but his beet-red face was more than enough to convey his affirmation.

Oneechan would be oh-so-happy and hugged him, even teared up a little. Sakuya, of course, was taken aback. But he just hugged her back.

10. (( XREADER OR OC OR ANYTHING ))
... Tbh any girl would be fine and this would be like a shoujo manga. He's hot and transfer student and smart AF. Damn, let me have you-

11. "You'll take care of him, right? He needs to realize that he has his own world, and he doesn't need to live his life for me."

She knows that whoever Sakuya fell with wouldn't be any guy, so she trusted his taste and believed the lover-to-be right away.

His sister was a troll of a matchmaker. I guarantee that. She would ask him out for dinner and leave the two in love. Sakuya would DEFINITELY confess, even if his face had already been dyed blood red, he'll make sure to say what's needed to say.

And then sister would have a recording of that.

12. If he were to pick between Mahiru/reader/OC with his sister, the answer is clear as crystal. He'd kill himself for his sister, why not leaving someone?

But sister wouldn't agree. She would cry and sob and other stuff, but Sakuya wasn't going to budge. She's the top priority. Such as in case of vampire attacks and stuffs.

13. If not, they'll live peacefully until sis found her love, they live together with Sakuya for a few years, which death glares would be involved everyday. Let's not forget that this Palmae boy is a yandere.

14. Bonus: If Mahiru wasn't taken in by Uncle Tooru and entered the same orphanage as Sakuya

Sakuya would almost be as close as with his sister with Mahiru. And vice versa. Even if it's hard for both to find friends, they'd manage together.

And then either they only become best friends, even after Sakuya surpassed Mahiru's class, or they got involved in a romance, that's up to you, readers.

15. Or he falls for someone in a university, idk. Anyway! After all those stuffs, they'll live happily ever after, loving each other-

Not before Papa strikes! Father returns from jail with a grudge, wanting to kill the sister. Sakuya, at all costs protect her.

Like your typical animanga/action movie, when he was about to get stabbed, sis saved him.

Sakuya was mortified. He beat his own father damn heavily. His sister was the only thing he had. How could he?

Luckily, before Papa got stabbed, sister stopped him. Just your stereotypical drama!

Then the happily ever after :)))
#AngstWithHappyEnding

16. As a matter of course, there's no vampire stuff unless shit happens with Tsubaki, but then again, Sakuya isn't going to be involved in drama. He avoided every trouble to evade getting troubles to her sister.

17. If sister gets hurt because of him, somehow, he'll get really suicidal and do extreme self-harming, punishing himself. Don't even mention what happens if sister died. He'd die in the most hurtful way possible.

If only I had my Tumblr *cri*

Credit to crazyanime3, the most Sakuya-loving person I know.

And I hate why I have to be late. I sacrifice my sleep, and I'll do it all over again for my love.