Polyshow

Polyshow is the POLY ship between Emu Ootori, Nene Kusanagi, Rui Kamishiro and Tenma Tsukasa from the Project SEKAI fandom.

Canon
Emu Ootori, Nene Kusanagi, Rui Kamishiro and Tsukasa Tenma are all from the same band : Wonderlands X Showtime.

Their story begins when Tsukasa receive an unknow message, titled "Untitled". He then gets teleported to a place with a big stage at the center, called Wonderlands SEKAI. This is a world born from his feelings, where he meets the Vocaloids Hastune Miku and KAITO. People who share the same feeling as him can also become of a part of this SEKAI. The first time he enters the SEKAI, only the vocaloids are present.

In Phoenix Wonderland, Tsukasa then goes to an audition room to take a job to work at the park. That's when we meet Emu, that is immediately interested by Tsukasa wanting to perform incredible shows.

A few day later, we meet Nene and Rui, as Tsukasa was walking down the streets and muttering to himself. Nene calls him a weirdo, and Rui says that he's interesting.

At his first day of job, Emu scares Tsukasa by dropping off the Wonder Stage. This is their first official meeting. Emu says that this was her way to welcome him, and that she wants to have incredible shows with him. Emu tells him that he didn't pass the audition, but that she really wants to perform with him, thus inviting him to the stage. Even when Tsukasa tries to leave, Emu begs him to stay.

After that, they end up in the Wonderlands SEKAI again, meaning that they share the same feeling on wanting to perform shows.

After going out of the SEKAI, they meet Rui and his several robots, that he calls "mechanical actors". He seems t perform show by telling stories with his robots being his actors. Rui and Emu are really impressed by his way to make shows. Because of that, they want to make him the third member of the park's performers, and so Tsukasa ask him to join them. Rui accepts on one condition, letting someone else he knows join, that person being Nene.

Controlling the robot Rui made for her, Nene and the others finally meet. Nene gets accepted in the group, and they're officially groupmates.

They all have the same passion of performing on stage, even though they express it differently. Them appearing in the same SEKAI proves that their feeling is the same. It makes them united in a way.

Fanon
Being from the same band, WonderlandsxShowtime, the four characters spend a lot of time together, and have several events dedicated to them. Because of how close the four of them are, the fandom started shipping them, as well as some other individual ships between them. It's not rare for a band in the Project SEKAI fandom to be shipped all together.

This poly relationship regroups a lot of other ships, known as : Emunene, Tsukaemu, EmuRui, RuiKasa, Ruinene and Tsukanene.