Pathfinder is my go-to. It's basically D&D 3.75. I started with 3rd edition, though, and my greatest adventuring team was in 3rd. We were playing an evil party. it started off, oh, we're adventurers, in it for gold and glory, we just happen to be evil, but it quickly got more ambitious. I was a tannaruuk, a demon-orc crossbreed. I roleplayed the Leadership feat. Every time we met some orcs, I would yell at them, asking who the chief was, kill him in one hit with my 24 strength power-attacking greataxe, then ask again. Before long, I had hundreds of orcs following me. The cleric, a demon-elf thing, suggested that we needed a better way to get around, and told our slightly crazed gnome wizard to get on it. The gnome had previously made himself a floating iron sphere to keep him safe, decided that a mobile fortress was the next step.
He had covered the window in his floating sphere with a cone to make it harder for people to shoot into, unintentionally making a flying teapot. This tells you a bit about the gnome in charge of making our fortress.
Much of the funding came from our thief, a murderous little halfling who spent every coin he had making a ring to be permanently invisible. Once he did, we never saw him again, though people would often die of unexplained throat slittings. He had the wizard slap silence spells on him and then cleaned out entire bank vaults on his own.
When the tower fortress was done, the gnome revealed that it wasn't just mobile. It could burrow. We asked why burrow instead of fly. He said because shut up. We immediately went about collecting more orcs, then surfaced in the middle of the kingdom's capitol city. About a thousand orcs set about killing everyone, while we went straight for the important people. The city fell in about 30 minutes. So we went from city to city, until finally all the heroes of the world banded against us. The cleric told us he could summon an avatar of his god if we held them off long enough, so he went to the top of the tower and started the ritual. The orcs fell quickly, and the heroes eventually killed my barbarian, the gnome wizard, and even the invisible rogue. They surged up the tower, and reached the cleric just as he finished.
It was at this point that we finally learned who our cleric worshiped. He followed an elder evil, the Devourer, an entity of pure destruction, banished at the beginning of time to the space between the worlds, and if it was ever released onto any of the planes again, it would instantly snuff out all of existence.
The last words to ever be uttered before the universe blinked out were, "Gentlemen, meet my God."