Kenji standing up to Ootake and refusing to get rid of Kanna , the first sign that he's back to his old Determinator self
"Love and peace...are on hold."
Kanna absolutely destroying the competition at Rabbit Navakov and then pretty much single-handedly ending a mob war and gaining the united forces as an army.
Not to mention she pulls the exact same trick that Jotaro used on Daniel J. D'Arby, having a crap hand but still winning by breaking her opponent with her superior poker face.
Otcho leaping through a church window to plant himself between Kanna and her would-be assassin.
Sadakiyo declaring that Kyoko is his student, before burning down Friend's childhood home.
Every single aspect of Kenji's return.
Especially the chapter it happens in. Right after Friend succeeds in becoming a god in the eyes of the people and the story reaches it Darkest Hour, we get a chapter that's only 3 pages long, consisting entirely of Kenji just casually driving down a highway on a motorcycle.