The opening part of the story, we have the MC as the final boss (demon lord?) of the game fighting against a horde of players wanting to take him down. In the middle (i think) he is helped by a dragon which is fought by the female leader of the army. Cant really remember much, but one tidbit is that even with all the fighting, the MC is featured as "never been wounded in his back". Ultimately, the MC falls and the game ends.

Now the gameworld fastforwards into the future and the MC plays a new char. 

One of the feature/bugs in game is that players sometimes create a split personality with their char, and now the MC will be facing off with his previous char(the demon lord.

Another detail is that the female leader the army is obsessed with the MC and in the current gametime will be (tries to be) together with the MC.