One idea could be exploring the backstories of the minor characters. For example, you could write about how a particular student ended up at Heavenly Host Elementary in the first place. Another idea is to create an alternate ending where the characters manage to escape the horrors of the school in a different way than in the original. Maybe they find a hidden passage that leads them directly out, but it has its own set of challenges.
A cool concept for a Corpse Party fanfic could be a time - travel story. Imagine a character somehow going back in time to before the events at Heavenly Host Elementary. They could then try to prevent the initial tragedy that led to the school becoming haunted, like stopping the earthquake that killed all those students in the first place.
You could create an OC who is a paranormal investigator. They hear about the rumors of Heavenly Host and decide to go there with their team to document any supernatural activity. However, once inside, they quickly realize that the situation is far more dangerous than they ever imagined. Their scientific knowledge and equipment might initially seem useful, but as the true nature of the place reveals itself, they have to rely on their wits and the help of any survivors they meet.
One idea could be that Satoshi and Yuka get separated from the rest of the group in the haunted school. As they try to find their way back, they encounter strange apparitions that seem to be connected to Yuka's past traumas. Another plot could involve Satoshi having to protect Yuka from a malevolent spirit that specifically targets her because of her innocent and pure nature. Maybe they find a hidden room in the school filled with old diaries that reveal secrets about the place and help them understand how to escape.
One idea could be a mystery adventure where Corpse and Sykkuno team up to solve a virtual riddle in a game world. They use their unique skills, Corpse's deep voice and strategic thinking, and Sykkuno's friendly and observant nature to crack the mystery.
One of the common themes is friendship. Even in the midst of all the horror, the original characters in the 'corpse party oc fanfic' often form bonds with other characters. They rely on each other to get through the terrifying situations. Also, mystery is a big part. The fanfics usually explore the secrets of Heavenly Host through the eyes of the OCs.
One common theme is probably survival. Given the nature of the Corpse Party universe, fanfics often revolve around Mayu and Shige trying to survive in the terrifying and dangerous situations. Another theme could be friendship, as they support each other through the horrors.
One interesting feature is the intense and spooky atmosphere. It really draws you into the horror setting. The character development is also quite good, making you care about the fates of the characters. Another feature is the branching storylines which offer different outcomes depending on the choices you make during the game.
One idea could be that at a college party, the Haikyuu characters are there incognito. They might be challenged to a volleyball game by some drunk college students who don't realize who they are. It could lead to a friendly yet competitive match with lots of fun banter and amazing volleyball plays.
One idea could be to set the fanfic at Camp Half - Blood. Have Percy's friends plan a surprise birthday party for him. They could organize a special quest just for the occasion, like finding a long - lost gift from Poseidon. The party could include a big bonfire with blue food and drinks, as blue is Percy's favorite color.
There is a 'corpse party oc fanfic' called 'OC's Struggle in Corpse Party'. In this fanfic, the original character has to face all the terrifying situations in the game world. The author does a great job of portraying the psychological state of the OC. It also makes use of the game's atmosphere and lore effectively, making it a very immersive read for Corpse Party fans.