Corpse God

Polka Shinoyama (四乃山ポルカ Shinoyama Poruka), known as the Corpse God (屍神殿 Kabane Shinden) in the Other World, is the main protagonist of Dead Mount Death Play.

As a human born with the Evil Eye, the Corpse God – not yet known as such – was sold to a Necromancer at the age of ten and studied Necromancy under her tutelage, eventually becoming an Undead himself. Though he wanted nothing more then to live a peaceful life, the Geldwood church spent centuries wanting nothing more than to see him dead.

To achieve the peaceful life he so desired, the Corpse God pursues the secret art of reincarnation with the intention of reincarnating as one of his fallen kinsmen. His spell works, but not as fully expected: rather than reincarnating as his kinsman, the Corpse God instead wakes in the corpse of the real Polka Shinoyama, freshly murdered in the Shinjuku ward of Tokyo, Japan.

Despite having reincarnated in a wrong body and world, the Corpse God has concluded this is his best chance yet at having a peaceful life. With the real Polka's permission, he has assumed Polka's name and identity along with Polka's body. His real name is unknown, as it is unpronounceable in Japanese.

Appearance
In his early years as an undead being, Polka walked the earth as a humanoid skeleton of adult stature, wreathing himself in a long, light-colored cloak with a hood and capacious sleeves.

Polka's final form as the Corpse God, centuries later, is unrecognizable. Where his previous skeletal frame was black and humanoid, his skeletal form as the Corpse God is white and bestial, resembling Earth vertebrates in some respects but too different to be directly analogous to any one creature. The horns adorning his cranium are bullish, and his hands have opposable digits.

However, while his axial skeleton has familiar paired ribs and his thoracic vertebral column familiar dorsal spines, he has three pairs of arms whose extraordinary length seem to compensate for the unusual caudal position of their (presumed) pectoral girdles; unusual, that is, when compared to those of hominids. Whatever lies below his lumbar vertebrae has been cloaked alternatively in cloth and shadow.

It is also unclear to what extent his skeletal form is reflective of creatures unique to the Other World, and how much of it is the result of necromancy magic. The ventral side of his rib cage displays unusual armoured plates instead of the long, flat sternum typical to primates, behind which he keeps – kept – his true form: a human brain, contained in a chain-suspended jar; considering the comments of Shagrua and his comrades, the armored plate could have been a custom design on his part to better protect his true self.

As the human "Polka Shinoyama," Polka has stayed true to the real Polka's hairstyle and fashion choices and is usually seen wearing the same outfit he found himself when he reincarnated. The neck wound that ended the real Polka's life has been stitched shut, and is stark against his throat; in addition, a lock of Polka's bangs has turned black post-murder. Thus, any photographs or videos depicting Polka with an unblemished neck and white bangs is likely depicting the real Polka prior to the murder attempt.

Personality
Above all else, Polka desires a quiet and peaceful existence and will go to extreme lengths to protect that peace. However, while he operates outside of human values, he is not without values and moral limits of his own - foremost among them his extraordinarily soft spot for children and inclination to protect them. He may view human souls as 'toys' but, since toys make children smile, has decided to treat human lives as 'precious' and will use them or protect them as he sees fit. His protective instinct has undermined his ultimate goal of a peaceful life on at least one occasion, as seen when he rescues Misaki Sakimiya from Lemmings.

Though Polka carries himself with a serious, confident air befitting of his true age, he is not without emotional expression. When he realizes he accidentally killed Misaki, he is visibly surprised and buries his face in his hands inn exasperation; when he is trying to pass himself off as the real Polka to Rozan Shinoyama, he smiles and chats away like a 'typical' teenage boy.

Still, his behavioral differences to the real Polka are notable enough that multiple Shinoyama family members have commented on it: where the real Polka is incredibly timid around women, our Polka speaks to them without problems and is unaffected when he finds himself in compromising situations with them.

Chronology
To be added.