Syonia

Syonia is the femlash ship between Sonia Nevermind and Genocider Syo in the Danganronpa fandom.

Canon
The two never canonically meet, due to both characters being in different games, with Syo being in Danganronpa: Trigger Happy Havoc, and Sonia being in Super Danganronpa 2: Goodbye Despair. Although, both are survivors of their respective killing games.

The two do have 1 interaction in Danganronpa V3's bonus mode, Ultimate Talent Development Plan. The event starts with Sonia meeting Genocider Syo, smiling and blushing, claiming her to be the "nation's very special murderous fiend". Syo proceeded to say Sonia's king would be in a panic that she's all alone with a violent murderer.

Sonia proceeded to talk about Syo's victims, and even made the point that all her victims are male, with Syo getting surprised that she knew she wouldn't be killed because she isn't an "adorable little man", and Syo also commenting that it was clear that Sonia did her research, but also commented that it was a bit creepy she was talking to a murderer like she was her friend, but forgave her because she read about her and her murders. Sonia apologized, saying that she was excited to meet *the* Genocider Syo in person, with her starting to laugh and telling her that she's treating a serial killer like a star.

Syo sighed, wishing she could talk to an adorable boy, so she would kill him later on. Sonia got confused and asked her how that relates to her characteristic as a murderer, and if its truly essential, with Syo being surprised that she doesn't know anything adorable, and is missing out in life, and that if she starts talking about it, she'll ramble on forever, and asked her if she really wanted to "go down the maiden's road". Sonia asked what she meant, and if it was related to women, but before Syo could answer, she sneezed, with Toko appearing. Toko was shocked she was in the presence of a princess, with Sonia getting upset she wasn't able to hear all the juicy information.

Fanon
The ship is not well known due to both characters never meeting canonically, and only have 1 interaction, and the fact the ship is a crossover ship between 2 characters from different games didn't help either, since crossover ships are not popular in the fandom. It is overshadowed by more popular ships for both characters. Sondham, Sounia, and Soniaki for Sonia, and Syomaru for Genocider Syo. Although, a small portion of the fandom enjoys the pair, the fact that Sonia is fascinated by serial killers, and that Syo is a serial killer herself, and the dynamic further fueled the two.