LitRPG Series. Published 2021?-23 on Kindle Unlimited. Set in Britain where MC is fused with a dead faery who is suppose to set up a dungeon.

[Vintagebooklvr]

This is a kind of gritty LitRPG, particularly the first one where the MC goes up against a gang of thugs who beat him and left him for dead with a borrowed sword from a man who taught him the basics in just a few hours. He fuses with a "faery" that crashed landed from a UFO that was suppose to set up one of multiple dungeons on Earth. He has limited time to find a place to put the dungeon core before it explodes him going with it. He saves a young girl with a puppy whose mother has been captured by a group of travelers, US would call gypsies. Eventually goes up against the group, rescues the mother and leaves behind the camp in hands of people who helped him destroy the group. Later the mother and daughter come back to find him where he is hiding out in a bar he frequented with his friends. The mother helps him to expand the area that his dungeon core encompasses. Eventually her husband, a British soldier, makes it back and joins them along with his sister who the MC almost hooked up with the night before the apocalypse began. There is a big fight in a supermarket when they go up against another dungeon core run by another "faery." It goes on and he becomes some sort of lord or god of lightning/storms.