The mansion of younger sister

From Elona Wiki

The sister's mansion is a "secret" location mentioned only in the book 'Strange Diary'. The book has been translated in the English version, but instructions are marked on the user created world map on how to find it.

There are a great number of small medals here for such a small area. It is also treated as a unique multi-level dungeon, like Lesimas, and adventurers will sometimes find artifacts here. You can also go back to it using a scroll of return at any time after you've discovered it.

v · d · e World
Towns	Derphy · Larna · Lumiest · Noyel · Palmia · Port Kapul · Vernis · Yowyn
Dungeons	Ancient Castle · Crypt of the Damned · Dragon's Nest · Lesimas · Minotaur's Nest · Mountain Pass · Puppy Cave · Pyramid · Tower of Fire · Yeek Cave · Fort of Chaos (Beast) · Fort of Chaos (Collapsed) · Fort of Chaos (Machine) · The Void
Other	Your Home · Cyber Dome · The Embassy · The Graveyard · The Mansion of Younger Sister · Miral and Garok's Workshop · The Truce Ground · Jail
Deeds	Farm · Dungeon · Museum · Ranch · Shop · Storage House