The idea for the anime is wonderful and interesting. In season 1, I had great hopes for the show but it felt rushed and all over the place. For example, you'd think that Mephisto would keep on sending people to try and kill Rin, but after Amaimon failed, it escalated into something very irrelevant to the existing plot. Rin got taken to the court by the paladin, and it soon escalated to Rin fighting Satan. You'd think that Rin fighting his own father and the strongest demon to exist would be really dramatic and exciting. Well, for me, I was just bored. The entire thing ended in 1 episode, and then it was like it never happened. Rin didn't even utter Satan's name after the fight (in season 2). Speaking of season 2, it was terrible. It's OK if you don't consider season 1, but season 2 just shifted completely off the plot. Rin's main goal of defeating Satan just vanished and he moved onto something else. Plus, the characters' actions were just very frustrating.