From the introduction:
JoJo’s Bizarre Adventure is a long-running (since 1986) manga series from Hirohiko Araki about the Joestar bloodline, and the various supernatural trials they face. It’s split into eight parts (the eighth of which is currently ongoing) each one featuring a different main character, often in a different part of the world. It starts with Phantom Blood, set in England at the end of the 19th century, which was a gothic, soap opera about extremely buff people, but by the time the second part, Battle Tendency, got started, the fights had developed into elaborate spectacles that showcased intellect just as much as the unusual abilities of its characters. This style would be defined by the introduction of Stands in the third part, Stardust Crusaders, the story arc that the series is most recognized for, within Japan and internationally.
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These are the sorts of events that this RPG is meant to facilitate; intense, clever, and occasionally absurd.