After collecting all three Pendants of Virtue, return to Hyrule Castle. A new path will open, leading you to the Master Sword. However, your triumph is short-lived as Yuga reappears, capturing Princess Zelda and transporting her to Lorule. You'll follow him through a dimensional rift, finding yourself in a dark, decaying mirror image of Hyrule.
Lorule is a desolate land, ravaged by its own history. The landscape is familiar yet twisted, and the enemies are more formidable. Your immediate goal is to find a way to navigate this new world and locate the captured Sages. The first area you'll explore in Lorule is often the equivalent of Hyrule Castle, but in a much more ruined state. Be prepared for tougher enemies and more complex environmental puzzles that leverage your merge ability in new ways. The atmosphere is much darker, reflecting the tragic past of this parallel realm.