@lycankeyy now your worldbuilding makes me want to flesh out my penillian ideas. Wtf.
I don't have any good drawings on hand right now but here's some incoherent unedited ramblings
These are just adding onto or tweaking the things we already know about them.
Background.
Penillians used to be an aquatic prey species. The species evolved rapidly to the point of outcompeting the others around them, and they quickly wiped out most of the creatures that once hunted them. The have become the ruling apex species of their planet, and only kept around the species that benefit them. Any magic or abilities they have are not their own, including their major shape-shifting abilities. Most normal Penillians can do is change the shape of their jaw, frills, spines, and horns. Which leads us into our next topic,
Physiology.
The reason many of them have frills and spines was to protect young Penillians from attacks to the throat by the creatures that hunted them, and they never fully devolved them, as well as the frills once behaving similarly to fins or gills. They have small horns that are mostly useless. The reason the species grew to the size they did is the increased amount of oxygen in the air, similar to the reason insects grew so big in the Cambrian period. They are covered in gray scales, the ones around their chest and forearms practically impenetrable by any means. Their tusks are often curved inwards or downwards, though may curve similar to elephants. This is known as the Emperor Gene, and causes changes in the facial structure and bones. This may cause difficulties in young Penillians, and most often don't survive past adolescence. Those that do are often revered. Their tusks are often adorned with jewels and decorative items.
Penillians are mainly carnivorous, but are technically omnivores. Their large teeth are sharp and serrated like a shark's. They are a top-heavy species with long arms and shorter legs, with a long finned tail. Their eyes behave very similar to a cat's.
Penillians heal incredibly fast. Their brains are wired to survive longer periods of time in the case of oxygen deprivation, and they can hold their breath for long periods of time, even after losing their gills. Their bones are denser than most other species. The inside of their mouths are purple like their blood.
(sorry for the shit quality I drew this with my finger on my phone-)
Society.
There are different factions of Penillians on their planet, but they are ruled by a false oligarchy, simply a cover-up for a dictatorship or a monarchy. The ruler typically wears a twisted silver and ruby crown, a resource that is incredibly rare on their planet. In order for a new leader of the group of the wealthy few to be chosen, a "royal" challenged must be declared by a relative, usually by an offspring or sibling, with some exceptions. Peace treaties with the Penillians are rare. They rarely wear anything (please, at least put some pants on....), but they usually wear cloaks to formal events, which are also rare. Some cloaks are thicker than others, but those are usually reserved for ship pilots. Cold vacuum of space, y'know?
Their laws are strict, and the death penalty is more common than one would think.
Planet.
Their planet used to be lush and covered in large oceans. However, after most species were wiped out, the world began to die. Plants and animals alike began to perish and fall into extinction. The reason they had their sights set for earth was because it was similar to what their own used to be, with more natural resources. The planet they live on is functionally dead, and would completely crumble if it weren't for them. The Penillians are a necessary evil, if you will.
Any questions? You have a question? No. DEATH BLAST