Non living beings have what is known as tether that binds them to an untangled essence and in some cases an ego where they gain their properties from, it is though that a soul is just a highly purified form of tether.
Tether is what gives properties to the things and places of their world, it is tied to the identity of things and how, alchemy itself works, through altering of the tether the object that is defined by it changes.
Tether has different qualities, it has been shown that the Materia itself is as defined by is tether as the tether itself, where legendary Materia such as orichalcum, the philosopher stone, adamantine, and the like. Hold a very strong tether that master smiths are able to alter to give it magic properties. But it is master smiths that would also find themselves refining and tempering the Materia, to clear out undesired essences to give space to what they want to project into the tether.
A flaming sword would require a master smith to spend days purifying the metal, and making a pure new sword, the sword would have a few moments where its tether would be susceptible, during those moments the master smith would tether imbue the essence through different means, the most common one being sacrificing crystalized essence etching it into the sword as the sword takes the essence for itself.
Places themself hold essence usually projected by the living creatures or strong essences that surround them, defining them, a place with the essence of swamp might connect their tether with their surroundings, growing affecting the tether that surrounds it growing. until the essence is completely contained. Though it might growth.
In theater is common for multiple essences to be present such is seen in big cities where the essence of civilization might be overwhelming, but on dangerous places the theater could also be bound to other essences like anger, murder, or greed, while a library might be imbue with essences of curiosity, order, or peace. All while still in the same city, and being connected through the same essence. People with weak egos, are found to be easily affected by this strong essences.