Primordials

Primordials are the first living beings to inhabit the Material Planes. Originally, they were beings of the Astral Plane and The Turmoil that just so happened to be in the area in which the material planes were created. Once the material planes were created, the primordials' ever shifting forms of thought and chaos instead became finite and immuteable. The immense power of the creation of the material planes ended up tearing the vast majority of primordials asunder and thier essence's were scattered throughout the Material Plane, First World, Netherworld and Ethereal Plane. These fragments of the primordials were created in the image of their progenitors and became the first living beings on the material planes. The original primordials (for the most part) survived their sundering and became lesser than what they were but still more powerful than the fragments that they created. In theory, the more fragments a primordial was split into, the weaker the power of the original primordial.
In rare cases however, the primordial may never have been torn asunder in the first place. These beings of immense power because known as Primordial Colossi. These one of a kind beings often had enough latent power to be outshined only by the gods. Fortunately for the material planes however, the power of the creation put these increbible beings into an indefinite slumber, only to be awoken under unique circumstances. Only a small few primordial colossi have ever been discovered and even fewer have ever awoken. It is considered extremely dangerous and the colossi remember their lives in the Astral Plane and Turmoil and may have gone made in the centuries since as they have been trapped on a stable, unchanging world in immutable bodies in vast constrast to their previous lives that they could shape and change with a thought.
Unlike all other beings, primordials still retain some of their latent power from the creation. Because of this, when they are destroyed, a powerful explosion occurs that sends out a wave of power and energy akin to what originally happened to them when the creation occurred. Anybody in the immediate area (this area grows/shrinks with the power of the primordial) is at risk of being destroyed by this wave of energy, anyone who survives however often gains a portion of the primordial's power shared amongst all others who also survived the encounter. When such an event happens to a primordial collosus the event is often world changing and only the strongest beings on the plane are likely to survive unless a significant amount of beings are in the area to help absorb the blast.