the SCIENCE! of elementals in the material plane

“Wild” elementals frequently emerge in the Material Plane around areas suffused with magic. Wild Elementals typically linger for a few hours, a few days, a few weeks at the most. Most commonly wild elementals appear around fonts of magical energy but they can also show up in areas where several spells were cast within a short span of time.
Wild elementals are neither good nor evil as mortals understand the terms. They will sometimes mimic the emotions that were present around the magic hat spawned them. An elemental spawned by magic used for performance art is probably going to be playful while an elemental spawned in the aftermath of a life or death magical duel is likely to be belligerent and violent.
The magic school in Uskala has opted to stagger examinations because if every wizarding student is experiencing exam stress at the same time, it can spawn large numbers of edgy spastic elementals.
Sometimes wild elementals spawn without any spells being cast. Wild elementals often spawn around fonts of magical energy. These elementals are often very hard to predict as they can be hostile, curious, playful, bored, industrious, almost anything.
The First Unmaking , was essentially caused by a flood of wild magic energy which unwittingly summoned wild elementals
“Conjured” elementals are physiological the same as wild elementals but they are all under the command of a spell-caster. They are brought into the material plane deliberately instead of accidentally.

Elemental Life Spans
It is unknown whether elementals are long lived creatures that spend 99% of their lives in the Elemental Plane or if elementals are purely a creature of the Material Plane living very short lifespans.
In truth, it's both.  Sometimes an elemental in the material plane is born and dies within a short period of time.  It's essence returns to The Elemental Plane, but it's unique individuality will be lost.   Other times, an elemental retains it's consciousness and memories of the material plane after returning to the Elemental Plane.

Hybrid elementals follow the same basic rules as common elementals.  They just are more powerful and more rare.
twisted elementals are perversions of natural elementals tainted by The Void.