My Original World Is Not Normal As I Expected (Honkai Impact 3rd)

Former hero Shin Takeru manages to return back to his home world after 300 years. There he finds out that his world was not as normal as he expected. While trying to getting used to his new reality is when his new adventure begins. Will he survive? Only time will tell. All Honkai Impact characters belong to Mihoyo and its related subsidiaries. My OCs come from my ass though. *I was bored and this idea kept on being stuck in my brain so I've decided to write the story to get it out of my system. Feel free to diss for my bad grammar since I have not written any kind of stories for years and English ain't my first language.