Looking for a story where the protagonist goes up against the world, or at least most of it. The protagonist can be a hero fighting bad guys, a villian fighting the good guys, an anti-hero, etc., as long as everyone's against him/her. Good examples would be these: The Main Character Hides His Strength, Code Geass (though, I'd prefer if the MC was more of an individual unit), Death Note, and Trigun.
Zetsuen no Tempest. The first half really feels exactly like that. Two main characters, fighting alone against the whole world.
Ok, then Kumo Desu ga, Nani ka? Starts off with a lone spider against all the monsters in the Labyrinth. That might satisfy you. But it gets way better later on when she's literally up against the whole world and its gods. (But you've probably read it already, haven't you?)
Maybe My Death Flags Show No Sign of Ending? Also Accelerator from Toaru Kagaku No Accelerator, though this is the side anime and he is a villain in the main one. I still recommend it, but you should watch the Toaru series by order first, if you haven’t, to understand the content. Or read the novel.
Yup. Already read it. For Death Flags, he didn't really fight the world's people, just his "destiny". For Accelerator, he was only ever a true villian in one or two arcs, after that, he chilled down and became some sort of deuteragonist.
Keyboard Immortal he basically always fights or u may say offends everyone because it was his job lol
Apotheosis of a demon MC is a girl in a fantasy world. The world is about to collapse because humans waste too much mana, so the world tree ask her to destroy all mana's sources in the world. So she destroy several kingdoms and is very OP. Technically, she fight against two world because she can teleport to Earth aswell. She is alone, but a minority workship her because they found out that she is in fact saving the world. However, all countries decide to allies to kill her (but they fail miserably).
Sage Monarch The antagonist who is someone from the future wants his totem (?) and practically the people of the future are his enemy among others.