Rhymien is a powerful shapeshifter with a specialty that focuses on mimicking other supernatural creatures. While Rhymien is able to transform into regular animals, he tends to imitate mythical beings: werewolves, dragons, mermaids, you name it.
There is a catch, naturally. Rhymien only gets the bare minimum of these creatures species abilities when he's transformed into them. For instance, as a werewolf he'll have claws and teeth, as a Dragon he'll have the power of flight and a thick hide, as a mermaid he'll be capable of breathing underwater. He can't transform people into any of these creatures, nor will he possess elemental abilities of any of them (fire from dragons, healing tears/fire that burns from a Phoenix, singing voice from a siren, etc.)
For all intents and purposes, Rhymien will have the scent and magical imprint of these creatures, able to trick people into believing he is whatever he is pretending to be. But to keep the act up for long periods of time, Rhymien has to get creative and use a quick wit and clever mind.
For those who force their way past this ruse and see his "true" form beyond the blue faceless being he lets the world see, their mind feels as if it is searing in pain. Worse, even, than looking at the sun. If they continue trying to determine how he looks after the initial burst of pain they will either go blind or go mad.
The only exception to this rule is Demi-Gods, Gods, and Eldrich beings.
The mortal mind is just not able to comprehend his true form safely.
Rhymien can partially transform (growing claws, etc.), but he can only shift into organic matter. He is competent at turning himself from one gender to the other and changing his apparent age, hair color, or other such physical attributes, allowing him to doppelgäng people for a short time. Note, this power doesn't allow for him to mimic voices or other attributes from specific people and he will revert to his humanoid shape if asleep or unconscious. Unfortunately, he has no skill at turning into things like trees/anything that isn't some form of animal, mythical beast, or humanoid.
For a better idea of how his powers work, here are a few more examples:
Arachne: Multiple appendages, multiple eyes, fangs. No ability to create web, no venom or poison.
Banshee: Ghost-like appearance, perhaps feels cold/dead. No wailing/screaming abilities.
Dragon: Wings, claws, and thick hide. No fire or other elemental effects.
Gargoyle: Flight/gliding, night eye. No ability for water manipulation or stone manipulation.
Genie: Can appear like a genie, including the ability to fit into a lamp. Doesn't actually have wish-granting magic or any elemental manipulation/teleportation.
Merfolk: Can breathe underwater/swim quickly and be used to underwater environments. No singing voice. Doesn't automatically understand the language of the merfolk.
Vampire: Appears like a vampire, fangs or colored eyes, dead-like skin, and the ability to drink blood. No vampiric blood or any other type of magic.
Werewolf: Claws and fur/tougher skin. Can't change people into werewolves.
Etc.
