Fantasy
Adachi doesn't think he's hated anyone as much as he does Souji Seta. It's not because he's the "hero", but because of how everyone else treats him, as if he was some sort of God, when he's obviously not. He has this mysterious air about him that makes all those dumb girls swoon at the slightest comment from him, and it makes Adachi sick.
He hates him. He wants to rub that smug kid's face in the hard gravel at Magatsu Inaba, stomp on his delicate, skinny fingers and shoot him straight through the heart. He sometimes imagines that he's fighting Souji in the TV World, and that he beats him. In his mind's eyes, he fantasizes about lifting poor, noble Souji by his bangs as he's crumpled on the ground after his defeat, and he can see perfectly that holier-than-thou glare as Adachi looks down at what a wretch he is, to show him he isn't this grand hero that's going to save the day.
It was his own, secret fantasy, one which he relived every day. Each daydream was a spectacular, epic battle between him and the silverette, and in his mind he was always the inevitable, indisputable winner.