[GrandComplete]

Fourze and Kaixa simply put these two as charcters together are like oil and water.

Gentaro is a optimistic, stubborn man who believes in friendship. But he can also see if people are being genuine. His attitude is why he made so many friends it led to him being friends with everyone.

Kusaka is the complete opposite he's a scheming, manipultive sociopath who would murder puppies if it would benfit him. In the show he would attempt to physcially and mentally harm Takumi, muder a child, is a racist and attempt some less than acceptiple things towards Mari. And in a later crossover attempt make a depressed Takumi to just give up since ,"he someone who has nothing to live for"

So Gentaro and Kusaka can't get along which leads to two types of story either Gentaro actually able to reform the guy by seeing past his nice persona and see just how messed up a person and geninuinly trying to help him. Or Kusaka ends up how he did in his own show with nothing Gentaro does changing him because if time travel can't change Kusaka what will? Giving us a bleak outlook that sometimes even with your best effort some people simply don't want help or your help can't change anything.