Kyouma are made of a core inside a physical body. A common characteristic to all Kyouma bodies is a horn on their head, apart from that, they can take many different forms in infinite combinations of animal and human-like features. Kyouma are able to evolve changing their body at will, growing extra parts of their body and getting special abilities (shapeshifting, invisibility, enhanced senses and/or strength, etc.) in a process that can take several dozen to hundreds of years. However they cannot change the nature of their core.
They are powerful creatures that are difficult to kill for normal humans. Kyouma are durable enough to survive the attack of average firearms, Fremy's attacks being an exception. To effectively kill a Kyouma, its core must be destroyed; If only the physical body is killed, the Kyouma can regenerate after some time. The blood of a Saint works like a dangerous poison to a Kyouma's core, acting like a neurotoxin that destroys their brain and motor functions. However, to kill a high level Kyouma about a cup of blood would be needed, making in impractical in most cases.
70% of Kyouma are low order and have intelligence similar to those of animals. The remaining 30% are intelligent and able to speak, however they do not feel emotions other than the urge to kill humans inherent to Kyouma. There are three special Kyouma who have their own will and emotions, who act as commanders for the rest of the Kyouma. Their names are Tgurneu, Cargikk, and Dozzu. Every Kyouma has pledged unconditional loyalty to one of the three commanders and will readily follow every single order even if it means death. During the battle of the first generation of Six Braves against the Majin, there was a Kyouma called Zophrair who also issued orders and was called "Demon King" by humans.