Yotsuyu Yagiyama

Yotsuyu Yagiyama (八木山夜露) is an antagonist appearing in Part VIII: JoJolion.

Yotsuyu is the architect of the Higashikata Family mansion. It is suggested that he knows of Josuke's complete former identity.

Appearance
Yagiyama is a man of slim build and average to above-average height, claiming to be 28 years old. He has shoulder-length, straight black hair with short bangs. His eyes are black, bearing a small, light triangular highlight.

He wears a headpiece of leaves; a collar with a pin bearing the letter H; and his arms and legs are clad in a dark, leathery material studded with small metallic spikes.

Later, his sex comes into question when his corpse is discovered to lack male external genital organs.

Personality
Cruel and calculating, Yotsuyu states that above all he desires social status. As Josuke states Yotsuyu is the type of person who will attack innocent people in order to show he is serious about his threats.

Apparently, he has some previous encounter with the man who fused with Yoshikage Kira.

Stand
Yotsuyu's Stand is I Am a Rock; able to attribute a force to targets attracting to one type of object at a time. Originally, perhaps as an optional Stand ability, he pulls a strong, clear, clinging material in a sheet from his eyes.

Rock Physiology
Calling his human nature into question, Yotsuyu is able to mimic rocks to a great extent, to the extent that is indistinguishable from other rocks.

Because of his rock form he doesn't need a place to sleep or rest. Although similar to humans, his body physiology can change to become rock, weakening his internal organs. This leads Norisuke to think he has comrades and belongs to a different species.

This also can be an effect of his mysterious food.

Synopsis
Before the events of Jojolion,Yotsuyu Yagiyama appears

Yotsuyu Yagiyama mysteriously appeared within the secret room below the Higashikata estate, watching Yasuho Hirose sleep. He then uses his Stand power to suffocate her, all in an attempt to draw out Paisley Park so he may examine it. Once Paisley Park manifests, he uses his Stand to trap it in place, and seems to be able to identify Paisley Park's unique abilities, such as it being a long-distance type Stand. While she is still trapped, he reveals that he is an architect and he is trying to scout out interesting properties, such as the secret room, and that he hopes that Josuke never retrieves his memories, appearing to know more than he lets on. Yasuho in a last ditch attempt to free herself manages to fold an origami bunch of bananas, which she successfully uses to trip Yagiyama, as they are still powered by Tsurugi Higashikata's Stand Paper Moon. Yagiyama falls onto a broken glass Yasuho had earlier tried to use to cut the film on her face, and in the confusion his Stand's power weakens, freeing Yasuho from the film, but he has mysteriously disappeared.

Later, he assaults Josuke and Norisuke as they attempt to gain access to the basement by causing large flower pots to accelerate towards them as he watches from the entrance, surprised Josuke would return to the location just to die again. In the end, Josuke used his soap bubbles to push Yotsuyu into the sea and make him talk, but Yagiyama's body started falling apart until he died.