The Vault of Thorns
The Council of Thorns created a demiplane lodged between the Material Plane and the First World called the Vault of Thorns. The druids used the Vault as a meeting place and extraplanar greenhouse, and they conducted experiments on strange plant life there. Due to the demiplane’s proximity to the First World, several fey creatures also came to inhabit the Vault of Thorns, mingling peacefully, for the most part, with the Council of Thorns.
The Vault of Thorns is a living demiplane. The floor is earth, and the walls and ceilings are constructed of an intertwined mass of living vegetation. If hacked through, these surfaces regenerate and reseal within 30 seconds. The vegetation is immune to nonmagical fire; when attacked with it, the vegetation only produces a 10-foot-diameter cloud of choking smoke. Unless otherwise noted, ceilings are 8 feet high, doors are made of thick ironwood branches that part to allow passage when touched, and normal light prevails throughout the demiplane (as sunlight shining through a forest canopy). Anyone spending more than an hour inside the Vault of Thorns can begin to notice that the “sun” never moves and the realm is stuck in an eternal state of midday.
The demiplane beyond the rooms of the Vault of Thorns is filled with thick vegetation and is virtually impassable. Any attempt to travel outside the confines of the Vault is extraordinarily difficult. Eventually, anyone moving through the demiplane finds herself back at the rooms that compose the actual Vault of Thorns.
While inside the Vault of Thorns, living creatures feel energized and more alive. In game terms, all inhabitants of the Vault do not fatigue, do not need to sleep (but still must spend the appropriate amount of time in prayer, study, or meditation to regain spells), and do not feel or suffer from hunger or thirst. Furthermore, spells of the healing subschool cast in the Vault of Thorns are empowered as though using the Empower Spell feat, but without using a higher-level spell slot.
Time does not move the same in The Vault of Thorns for every 12 hours that pass in the vault only five minutes pass in the prime.