I’ve had a story idea sitting in the back of my head for a while now, but I don’t know if it’s good enough to become a full-fledged story.
MC is a Japanese teenager named Ryosuke Shoichiro. His childhood friend invites him to meet her at the park. When he gets there, he sees her lovely face being bitten off by a giant monster. A clan of monster slayers rescues him and tells him the only way to bring her back to life is to feed her the blood of the clan leaders sister which the clan leader promised to protect. Clan leader does know if she should break the promise though because if she does chlid hood friend lives.
criticism is welcome.
Which one is supposed to be his surname? Both Ryosuke and Shoichiro are given names, not surnames.
Japanese names have given name and surname, just like westerners. However, unlike westerners, Japanese names have no middle names. It's always two: given name and surname. No Japanese name will ever have three names.
Westerners generally assume that Japanese names start with surname, then given name, but this is not always true. When written in Japanese, the surname is always first. When written in English, it follows western convention, which is given name goes first.
For example, Ai-chan's name in English is Airi Shiina, which follows the western convention, which is given name first and surname second. But in Japanese, Ai-chan's name is 椎名愛李 written in furigana as しいなあいり (Shiina Airi). A given name can be written in either kanji or hiragana, but a surname is always written in kanji. 椎名 means 'distinguished oak' referring to 'a strong tree respected for its contributions' but can also mean 'a strong, unmoving personage whose feet holds strong against the wind'.
You would've saved yourself a lot of time and headache if you just use English names. But Ai-chan understands if you want to get out of your comfort zone and try something new. While most modern Japanese names no longer have meaning, parents still name their children hoping they'd grow up following the meaning of their name. At the very least, you need to know the formatting of Japanese names if you want to use them.
Japanese names in general do not have gender attached to them and are mostly gender neutral, though some names are attached to one gender more often. For example, Kaoru is used to name both male and female, but Kaoruko is always female. Similarly, Yuki can be both male and female name, but Yukiko is always female and Yukio is always male.
You can't really just invent a new surname either as most native Japanese surnames was archived in the Meiji era.
An easy way to construct a Japanese name if you don't care about meaning is to look at the names of your favourite pornstars, artists or anime characters and mix and match their names. You just need to know which one is the surname and which one is the given name. While Ai-chan did say the given name is mentioned first in English, not everyone follow this rule, either due to confusion or plain stubbornness.