More of an engine than a system at this point, Legacy is a game about... legacy, each player plays as an entire faction of people, guiding their history, their conflicts, and their choices. Eventually, the game zooms in, showing the story of a couple of notable heroes from each PC faction going on dangerous quests to save people. Legacy is also full of many different settings for playing different tones of play. Including Rhapsody of Blood (a Castlevania inspired setting), Worldsoul (a sci-fi colonization game), Generation Ship (a game about colonizing a ship full of humans who awoke way too early), and Free from the Yoke (a game about being a group of medieval houses recovering from the local empire's fall)
This game is sick. The book is beautiful, the rules seemed fairly tight, and the supplemental mechanics (world-building, etc) were really really cool. We only played a 2-session one shot so we sadly didn't get to the legacy stuff, but I was very into it and wanted to keep going.