Norisuke Higashikata IV

Norisuke Higashikata IV is the guardian of the protagonist during his attempt to salvage his memories, though appears to be an antagonist in his own right.

Personality
Norisuke IV is the head of Higashikata fruit company which was established by his great grandfather with the prize money from the Steel Ball Run race. He initially seems very glad to help the protagonist and even puts him over his own son, Joushuu on several occasions. He also holds an interest in personality types, and describes himself as a "yankee".

Towards the end of his introduction, however, he starts acting secretative and bossy, especially with the words "my word is the law in this house". Though he makes it a point to kill the protagonist after witnessing his supposed romantic affair with Daiya, Norisuke IV does not do anything, preferring to "keep Josuke a slave and prevent him from retrieving his memories".

Synopsis
Later on in the series, he walks in on Josuke's supposed affair with Daiya, swearing that he'll kill him later. He also knows of Daiya's stand ability, California King Bed. Since stands can be passed down genetically and Norisuke is capable of perceiving stands, it is possible that he also has a stand of his own.

Despite swearing vengeance on the protagonist for his affair with Daiya, he quells a confrontation between Joushuu and the Protagonist telling Joushuu to get along with him and to not embarrass him.

Trivia

 * Of note is that his birth name was also "Josuke Higashikata", the same name that the protagonist takes up. The fact that his mother's name is also Tomoko implies that Norisuke IV may be considered a Steel Ball Run counterpart of the Part IV protagonist.