I started watching JoJo's Bizarre Adventure, and I was going to comment on how Jonathon transforms from harmless, carefree, rich boy - to the most powerful force in the universe literally between episode 1 & 2.

But, I see the ultimate comparison is pretty obvious:
https://jojowiki.com/Blog:Fist_of_the_North_Star%27s_influence_on_JoJo%27s_Bizarre_Adventure