Location from Solo Leveling by Chugong
A System-generated instance dungeon that Jinwoo cleared floor by floor — a massive demonic fortress where he extracted Igris and leveled up dramatically.
The Demon Castle is a System-generated instance dungeon — a private dungeon accessible only through the System interface. It's structured as a multi-floor tower filled with demon nobles and their armies. Jinwoo cleared it floor by floor over multiple visits, gaining experience, items, and shadow soldiers. It's where he extracted Igris from a red-armored knight guarding the upper floors, and where he met Esil, a demon noble who guided him through the Castle's politics. The Demon Castle is also where Jinwoo found the Orb of Avarice and other powerful items.
Also known as: Demon Castle, The Demon Castle, Demon Tower