Tsukasaki

Tsukasaki is the family ship between Saki and Tsukasa from the Project SEKAI fandom.

Canon
Tsukasa and Saki are siblings, with Tsukasa being almost a year older than Saki. When they were young, Tsukasa and Saki watched a show together, and they both said that the star of the show is amazing. Tsukasa is happy to see that Saki is smiling after so long. Saki fell sick and was hospitalized when she was young, so Tsukasa took care of her and performed shows to make her smile.

Years later Tsukasa is in his room when Saki comes in to tell him to not make much of a racket. She then wishes him luck for his job interview. Tsukasa asks her about school, telling her to not overdo herself because she just got better compared to when she was sick. Saki thanks him for asking but insists she's fine, and Tsukasa says that’s good. Saki says that she’s happy that he’s getting closer to his dream, also asking him why he wants to be a star. He responds, and Saki leaves the room, telling him to do his best. After Tsukasa visits the Wonderland SEKAI and he is back in his room, Saki reminds him to go to his job interview before he's late.

In Tsukasa’s room, Saki walks in once again and asks him if he’s writing a new play. He tells her yes, and Saki asks when he’s preforming it since she wants to come see. Tsukasa asks her if she’s feeling okay since she started working in a cafe and joined a club. She says yes and that she should make sure not to get carried away because she doesn’t want to bother Tsukasa and the others. Tsukasa then does a show for Saki, and she thanks him. They then talk about Saki’s toys, and she wish's him luck with his new show, also mentioning she sees him working hard she gets energy.

Doll Festival at the Tenma's
As kids, Tsukasa heard Saki in the hospital saying that she wanted to see their dolls. Tsukasa ran home to get the emperor and empress dolls before he ran back to the hospital. Tsukasa tripped and fell, getting the dolls dirty. Tsukasa thought to himself that he couldn't show the dolls to Saki, but he showed them to her anyways because he was her big brother that had to make her smile. Saki noticed that Tsukasa was hurt worse than the dolls, and she was really happy that Tsukasa came all that way for her. She was so happy that she might have started crying. Saki smiled and thanked Tsukasa, but Tsukasa couldn't help but think about how he got the dolls dirty.

Tsukasa remembered the look on Saki's face and couldn't bare to see her like that. Tsukasa couldn't get replacement dolls with his allowance, so he devised a plan to buy Saki the perfect dolls one day. Saki's parents offered to buy Saki new dolls, but Saki liked the dolls the way they were because Tsukasa and her were tied together by the dolls. The dolls were the most important thing in the world to Saki.

Tsukasa finally gets replacement dolls for Saki years later, but Saki is upset because the replacement dolls aren't hers and because Tsukasa forgot how much the dolls meant to her. Saki later regrets saying all of that to Tsukasa, and she thinks he's mad at her because he won't read her messages. Though, it turns out that Tsukasa just left his phone at home. Meanwhile, Tsukasa thinks that Saki is mad at him and that he shouldn't show up to the Doll Festival party or else he'll ruin the mood. Tsukasa shows up at the party anyways, and Saki and him both apologize to each other and communicate their respective sides of the story. They use both the old and new dolls to celebrate.

Quotes
"Call me if you ever start feeling lonely again! I'll be by your side in no time!"

- Young Tsukasa to Saki in "Doll Festival at the Tenma's" Chapter 3

"I can't say that I know Tsukasa-san all that well but... I just don't think he'd forget about something like that. I mean, you mean everything to him, right?"

- Honami to Saki in "Doll Festival at the Tenma's" Chapter 5

"Saki!! My precious little sister! The best little sister anyone could ask for!!"

- Tsukasa in "Doll Festival at the Tenma's" Chapter 8

Fanon
Tsukasaki sailed as a result of the two canonically being siblings. Tsukasaki is very unpopular as a het ship in the Western fandom, while it is quite popular in the Eastern fandom (especially in the South Korean fandom). Most people may prefer to ship RuiKasa, Shihosaki or Ichisaki romantically. People like their wholesome dynamic as a familyship. They're also sometimes headcanoned to be adoptive siblings with Touya, due to his unstable home life.

Fandom
FAN FICTION

ART

TWITTER
 * Korean Tenma Siblings Account

Trivia

 * Their ship is referred to with the "🌟🎹" emojis.
 * They have a cover of Pinocchio-P's song "Cosmospice", which was specfically created for the Nissin Cup Ramen collaboration with Project SEKAI.

Variations

 * Tenma Siblings refers to the ship between Touya Aoyagi, Saki and Tsukasa