For those who haven't heard of Touhou, it's a bullet hell series that was created by ZUN. The gameplay is relatively simple, but there are different levels that increase the intensity and make it really hard. Check YouTube and you'll see a ton of people who have heard of and own the game. It's also a computer game so no consoles. It has a ton of characters and a huge fanbase as well. It's so popular that people have made a fanmade anime of it. I recommend you see games like Embodiment of the Scarlet Devil,Perfect Cherry Blossom, and Scarlet Water Rhapsody for they are my favorites. So the characters I'll be including in here are

Hakurei Reimu: She's like the main character in the games. She's a shrine maiden for the Hakurei shrine and goes off to fight yokai. She also has magic relating to the Yin-Yang.

Kirisame Marisa: She's Reimu's close friend as well as a witch. She's like a tomboy that ends her sentences with "da ze." She's the kind to kick ass and tell a good joke too. She's human but her magic makes her almost like a yokai.

Remillia Scarlet: She's a vampire and also the main antagonist in Embodiment of Scarlet Devil. After the events of that game she obtained a (sort of) good relationship with Reimu. She can be quite terrifying, obviously because she's a vampire, but she's also powerful. Especially because she wields the power of Dracula's cradle.

Patchouli Knowledge:
Patchouli is a very powerful sorceress that lives in the library of the Scarlet Devil Manor. She's a close acquaintance of Remilia that is able to cast spells relating to any of the elements. She can combine them and leave fatal damage. But she has asthma as well which can be a hindrance.

Sanae Kochiya: She's a shrine maiden from the Moriya shrine, also a sort of rival to Reimu. She's good hearted and occasionally helps Reimu with yokai's. She's also a boss in the game Mountain of Faith. According to the games and sources Sanae came to Gensokyo from the outside world (human world.) and she made a new life in Gensokyo dedicating herself to the shrine and it's god.

Youmu Konpaku: She's a half ghost half human servant to the ghost princess Yuyuko. She has a double katana blade and calls upon the power of an old cherry blossom tree that is said to hold spiritual power.

Alice Margatroid: Alice is similar to Patchouli and Marisa. She uses magic to command her dolls giving her the nickname the Puppet master. Her dolls are like soldiers that attack and defend on her demand.

Aya Shameimaru: She's a Tengu and the fastest being in Gensokyo. She uses her speed as well as maple leaf fan in battle whipping up winds as powerful as a god. She's also Gensokyo's top reporter and always ready to discover a scoop.

These are the characters that will be transported out of Gensokyo.

Although another important character is
Yukari Yakumo: She's a crafty one, but she's also powerful because she's the one that guards and senses the border between Gensokyo and the outside world. She also uses that to her advantage making portals between dimensions to her advantage.

I think that's enough information, also I don't any characters or images in this fanfiction.