Girls' Frontline: My Apocalypse with Dolls

A hacker, a young man who doesn't belong to this world, a cleanup man.
Girls suddenly emerged from the closet, holding guns, their eyes filled with determination, composure, or joy.
He knew them, and they loved him deeply. They discovered that the world was in turmoil, with biohazards and Umbrella Corporation. He had the ability, he had them, and he felt he could give it a try.
He was indeed going further and further down the road to success. However, things didn't always turn out as he wished...
P.S.: Slice of life unfolds first, then the main storyline takes place in a fictional world. Please don't relate this to reality. This book has a lot of sweet moments...