Shadow has two forms; a battle form, or a beast form, and a human form.
While in beast form, Shadow has a body resembling a giant scorpion, and large, blade-like legs. He also has red eyes and fangs, much larger than his teeth, on the corners of his mouth and jaw. While in his human form, Shadow has gray skin and black eyes with red irises. He wears a jumpsuit with a gap in the middle, showing most of his chest. He also has what seems to be half of his beast form's head worn over his head, which has several appendages which connect to another body underneath. Shadow's human form seems to combine with his beast form, as his legs are attached to another body similar to his beast form.
Shadow is sometimes portrayed in a more harmless, chibi-like form, with only half of his head appearing from the ground and round, red eyes.
Shadow is very calm and a bit passive. He will rarely ever cause trouble or attack anyone unless Muyeong directs him to. Occasionally he will wander off on his own, but when he does it is likely to be inconvenient. Because of this, Muyeong will get irritated at the yongma, and Shadow's lack of ability to speak or explain creates a rather comical effect.
The full extent of Shadow's abilities is likely still being revealed but he has demonstrated several unique skills.
Teleportation - Shadow is able to transport either Muyeong or just himself over large distances fairly quickly, by (presumably) traveling through shadows. Though Muyeong has stated that he doesn't know if he can take other people with him, Shade was seen transporting Gamunbi along with Ignatio so it can be assumed Shadow is likely able to do this as well.
Regeneration - Though Shadow can be injured, he has a very high regeneration rate and it is quite difficult to actually damage his body. Leon's poison, however, can not only damage him but significantly slow his regeneration rate.
Shields - Shadow's body can be damaged but it is extremely difficult to do so with normal weapons. As such he can easily use his body to shield Muyeong from incoming attacks.
Transformation - Shadow has a large beast form that demonstrates extreme strength and power but he also has a Human form (which is usually seen as being partially emerged out of the beast-like form) he can take as well.
Shadow can attack not just with his actual body but also with tendrils of shadow that seem to act as blades or whips and can damage opponents as well. When in the midst of battle, his wide variety of skills make him quite a formidable opponent and the perfect partner for Muyeong.
According to Muyeong, Shadow is unable to stay separated from him for extended periods of time, the farther the distance, the shorter the time he can be away. If Shadow is very far, the most he can stay away is an hour, and even if forced, a maximum of three to four hours. After that, Shadow has to return to Muyeong.
- Strangely enough, Shadow is as equally afraid of Cheoyong as he is of Muyeong.
- Shadow does not like to be in the daylight in his human form.