I read this story originally on royalroad. I believe the author then moved the story from here to an original site. The story as far as i remember is a virtual reality title. The premise is that there are mutliple floors and they need to battle a big floor boss at the end of each floor. This is done as a team battle where everyone in the floor can participate. The mc is a guy and i remember him getting the kill credit for at least one of the floor masters.
The mc had some sort of powers that were originally associated with darkness. He was then drilling in some tunnels and ran into a zone that was associated with the gods/masters of light related powers. They then offered him the chance to change from his darkness related powers to those of light. he accpeted and it turns out that he had a demon king level spirit of darkness in him or something along those lines. after he got his new powers he had to go through training with certain gods and it ended with waves of enemies and the last wave was a battle of like 100's of monsters or something along those lines. I believe they were orcs. after this battle he returned to the main zone of the game.
In this zone he went back to his auction house or store he had set up and found out it was robbed by the main girl of the story. She was like his archrival turned friend. They had fought a few times and he always won. One specific fight i believe happened on a train. so he heads to her guild to find her and get his gold back. He ends up bringing his follower/summon that he got during the god training and they fight their way through the guild. Hes screaming about where all his gold went and the girl responds that she thought he was gone since he left for so long and she couldnt contact him for a long time. So he uses some move that he obtained from the god area that makes the person who its used on experience all the pain of those that had been killed since the last time it was used or something like that.
Most of what i wrote about with the god training happened in the last few chapters that were written. Which is basically all i remember. It has been a long time since i read this story. Somewhere along the lines of 3-5+ years.
Any help in finding the story would be greatly appreciated.