Having enemies does not always mean you loathe them...
Sometimes it means you love them but you're just too proud to admit it.
"I hate you...but I love you, I miss you and I need you but I hate you."
A hero, and a villain. Two known people for hating each other and having fights in front of millions civilians. The hero, now has a sidekick but this sidekick doesn't seem like just a sidekick, and the villain doesn't like this.
The villain doesn't understand these feelings about this "sidekick" it's like jealousy, but he holds it in. He doesn't love the hero, or does he?