Gwishin (or Ghost) is an existence used by Chau Yoong. Not much is known about him, not even what exactly he is supposed to be. A few theories surrounding what he is are that Ghost is Chau Yoong's Yongma, or he is a soul of a Chachaoong that Chau Yoong (who has the ability to manipulate souls) killed in the past.
Gwishin somewhat has the appearance of a samurai. His armour is covered in red, yellow, and blue scales and he dons a red cape. His helmet is gold and scaled, and shadows his face. Most notable are his very large hands (which seem to hint at him being a Yongma, as most Yongma seem to have this trait). However he does not possess any visible arms.