The Seree are gone, but the vaults remain. But the gnawing of time cares nothing for secrets..
On the big map, the vault is located in the foothills of the Wintpeaks, north of Aridenn, but you could situate it in any mountain or escarpment. Relatively close to an existing settlement is better, since that gives a greater chance that there are some 'river people' encountering the vault servants, or exhibiting odd, magical side-effects from the vault's runoff water.
There's very little loose treasure in the vault, but remember that nearly every skull contains a wizard flower!
Vitrum Aquae for Player Characters
If PC spellcasters experiment with the vitrum aquae ritual, it's basically an opportunity for a permanently-memorized spell (which uses up the spell memorization slot), at the cost of a point of one or all of Int, Wis, Cha.
The quantity and quality of gemstone should be commensurate with the level of the spell being crystallized - anything less will worsen the side effects, which include:
- Losing more points from Int, Wis or Cha
- The spell uses up one or more additional spell slots
- The spell is miscast, and can never again be cast in its correct form, and always comes with either minor or major side effects (e.g. fireball always detonates at the wizard's fingertip, invisibility can only be cast on someone else, levitation only works upwards, the wizard can never fly to the east, etc.)