Peaceful beings of pure light, these unbelievably intelligent creatures are deceivingly aggressive.

Celestial

pastels and whites, bioluminescent features

Assumes the form of a preexisting animal

Quite large, twice the size of their animal counterparts

twice the weight of their animal counterparts

Starlings have bioluminescent features. Which feature and what colour is entirely dependent on the individual starling. They can dim and brighten these features as they please. Many people speculate they use this as a form of communication between each other.

dependant on their animal counterpart

Starlings are not aggressive in the sense that they will kill, but they're aggressive in the sense that they'll bully a person relentlessly for the slightest transgression.

Starlings know exactly what will annoy a human most, going for that method of attack primarily.

The only time a starling may kill is if it is attacked. They are relentless when it comes to taking out a threat and will even use things like sharp rocks or unattended throwing knives to do so.

Starlings are fast, moving at about 50 miles per hour on land and even faster if they can fly.

Their greatest feat is their intelligence. It's theorised that a Starling can have the intelligence of a human adult in extreme cases.

All starlings have at least a bit of pride, and that's what gets most of them killed.

Starlings have been observed making sounds many would describe as singing, incredibly melodic and like honey on the ears.

They can hear from miles away. If a Starling seems not to detect your presence, it's either asleep or doesn't believe you're a threat.

They are completely blind, relying on echolocation to move around the world. Scientists speculate their songs are actually echolocation.

Many people equivocate starling intelligence to that of orca whales. They're not as intelligent as humans, but they have been observed to be incredibly smart and may even have their own language.

Starlings are a bit picky as to where they make their home, never willingly stepping foot in places where Yggdrasil's influence is scarce.

While they can eat meat and animal byproducts, most choose to feast on naturally sweet foods like fruits.

Starlings are usually hunted by the same animals as their animal counterparts, though any animal that can actually capture and kill a starling will probably give up trying to eat it after a while.

All starlings are embodiments of Yggdrasil's light, literally creating something out of nothing.