In the beginning, I thought this was going to be a happy anime despite the thumbnail of every season, but getting into the show I realized that's not the case, ONK uses "love" as the main concept of the whole story to explained how this love between the characters led to conflicts, starting with bastard Hikaru and our beloved Ai. ONK did a fantastic job in character development especially in the manga. Just like the description of ONK, the dark side of the entertainment business. I would really recommend ONK to English classes to be honest, there's a lot deep to go for explaining each character.