Polka Shinoyama

Polka Shinoyama (四乃山ポルカ Shinoyama Poruka) is the second son of Rozan Shinoyama and one of two heirs to the Shinoyama Financial Group. He possesses the Elemental Eye.

Shortly after running away from home, Polka is assassinated by contract killer Misaki Sakimiya. The Corpse God reincarnates into Polka's freshly murdered body, anchoring Polka's spirit, and soon transfers Polka's spirit to one of Takumi Kuruya's drones. Later, he again transfers Polka's spirit to a stuffed bonito shark toy.

Polka has given permission for the Corpse God to use his name and identity, and—as the shark plush—currently accompanies the Corpse God wherever he goes.

Appearance
Polka has short white hair and pale blue eyes. On the day of his murder, he is wearing a light-colored T-shirt and jeans. Any photographs or videos featuring Polka with a black lock of bangs and a neck scar are featuring his body post-murder as occupied by the Corpse God.

As a bonito shark plush, he is small enough to be carried in a jacket hood. The shark has two visible screws or buttons in its tail and on its top, and visible stitch marks on its snout. Due to the Corpse God's magic, the plush toy is capable of movement and conveying Polka's emotions to some degree: not only can its mouth resemble a smile or frown, its whole body can 'blush' when Polka is embarrassed.

According to Sayo Shinoyama, the toy shark is the same as the shark from the movie Sharkborg from Hell (part two), and can thus be presumed to be Sharkborg merchandise.

Personality
Polka's relatives know him as a 'scaredy-cat', so timid as to be almost entirely incapable of talking to girls. This assessment appears to be true to some extent, as he-as-the-shark blushes from snout to tail the first time Misaki Sakimiya cuddles him against her chest; he also trembles, albeit with good reason, upon learning that a family member may have been the one to order his assassination. Furthermore, the Corpse God's calm confidence and firm vow to protect Shizuki and Kazuki Shinoyama strikes the twins and incredibly unlike the half uncle they know.

While Polka may generally be timid, he has on at least two occasions—first as a toddler, and again as a teenaged shark plush—the courage to put his life on the line for those he cares about, using his own body as a shield. This courage, along with his willingness to forgive the very person who murdered him, exemplifies the kindness at Polka's core.

Polka's insistence that the Corpse God feel free to borrow his identity may indeed be attributed to that kindness as well as a matter of safety; with that said, Polka appears to genuinely enjoy being a shark and has cheerfully called the experience 'cool' and 'swank'.

In using the shark's whole body to express himself, he can be incredibly animated and expressive despite—or perhaps, because of—his body's limitations. As such, even his father Rozan Shinoyama can tell that he is honestly happy with his current form—although Polka has expressed similar enthusiasm at the idea of being an android, personally suggesting outlandish features such as wielding a rock drill and flight capabilities.

Though Polka's happiness as a shark is certainly derived from the sheer novelty of the experience, it is strongly implied that he views his current situation as comparatively better than the one he ran away from. And though his feelings and concerns immediately prior to running away are not yet entirely clear, his demonstrated disinterest in money hints at the family problems that troubled him.

Polka's time as a shark and companionship with the Corpse God's coterie may be changing him as a person; that he is spending constant time with Misaki is almost certainly positively improving his confidence around girls, as his embarrassment is less acute the second time Misaki cuddles him against her chest.

Chronology
To be added.