The Plant Appraiser - Rai Mamezuku (31) (植物鑑定人－豆銑 礼(31) Shokubutsu Kanteinin - Mamezuku Rai (31)) is the fifteenth story arc of JoJolion.
Josuke and Yasuho finally meet the plant appraiser Rai Mamezuku, who has just hijacked the bus and demands that Josuke protects him first and foremost, as they are now under attack from an enemy Stand.
Rai, an analytical and unpleasant individual, eventually stops in a parking and invites Josuke and Yasuho to a chairlift, revealed to be his home, then cooks them a Romanoff cream. All the while, Rai and Josuke discuss. The enemy is a brand new organization which is surely powerful and desires the new breed of Rokakaka, as it allows people to defy death. Because of the enemy, Rai wants Josuke to make his protection the top priority. He is the only one who can find the Rokakaka and must be kept safe at any cost.
Rai wants to reach the 8th pole of his chairlift to retrieve something but a tree sneaks on the group and releases a swarm of cube-like Stands who can dissolve flesh and create holes on the body. Josuke instinctively protects Yasuho, which costs Rai his hand. Miffed, Rai throws Yasuho down the chairlift to expose her to the enemy attack and observe their power. Soon enough, Yasuho is attacked by in fact two Rock Humans. One of them human-like and possessing the cube Stands, the other having the form of a threaded vehicle who moves underground and in whom is encased the first foe.
- 065 (912). The Plant Appraiser - Rai Mamezuku (31), Part 1
- 066 (913). The Plant Appraiser - Rai Mamezuku (31), Part 2
- 067 (914). The Plant Appraiser - Rai Mamezuku (31), Part 3