[Eldara] Death, Elementals, and Magic Crystals
Mortal souls disperse upon death, their energy returning into the immediate surroundings of the thing that died. The process of dispersion can take anywhere from seconds to hours and in some extremely rare cases, days, in which case it's more of a gradual degradation into nothingness. Once someone is dead, they can not be brought back, not even by the gods, as the mortal soul is way too complex for even them to recreate fully. If they attempted to do so, the best they could do would be a physical copy of the body and some semblance of the soul, which would nonetheless be very obviously not the deceased person. What might happen during the process of dispersion is that if the dying soul is in high enough concentrations of magical energy, its constituent parts might fuse together instead of fizzling away, forming an elemental. The elemental will have some echoes of their personality (and in fact there are so-called elemental traps that capture the full soul at the moment of death, trying to keep as much of the person alove as possible), but will, again, not be the deceased person. Instead, it is a new being; a sentient string of magical energy with a single, pure magical element to its very existence. A newborn elemental is very active and highly temperamental, but over time they tend to calm down, and if they don't manage to find a good source of magic to keep them active, they get slow and eventually settle down in a single place, where they then crystallize, creating a shell of crystal around themselves, whose structure is perfectly fit to store the elemental's energy. These crystals can be collected and used by mages as batteries or by non-mages as piezo-arcanic sources of magic (squeezing them together agitates the elemental inside and makes it do something related to its element). If the crystal is left undisturbed long enough, it will sibsume the elemental entirely, effectively killing it. These crystals are typically stronger but react the same way as if the elemental was still in them. The notable difference is that they can absorb (and trap) new ones, as well as form them out of nearby dying souls (thus an elemental trap).