Sword World is a Japanese TTRPG created by Group SNE. It is one of the most popular tabletop games in Japan, selling over 10 million copies of rulebooks, light novels, and replays (basically campaigns and game sessions turned into novels).
Sword World was first published in 1989, as an RPG supplement for Record of Lodoss War. Originally Lodoss was planned on becoming an official setting for Dungeons & Dragons, but the pitch was turned down by TSR, and Sword World was born. The first edition, Sword World 1.0, features the world of Forcelia, which contains the lands of Lodoss, Crystania (of Legend of Crystania), and Alecrast (of Rune Soldier). The second edition, Sword World 2.0, was released in 2008 and has an entirely new setting in the form of Raxia, and Sword World 2.5 released in 2018 was a ten-year anniversary revision of the rules.
Although none of the editions have ever been released outside Japan, there are translations that exist, though mostly for SW 2.0. Because of this, I will mostly be posting stuff from SW 2.0, but expect stuff from other related material and series as well.