The reason why the Abbey Dean wanted to help the Hierarch in the 42nd episode of The Night 2 was because the Hierarch was a very powerful character with unique abilities and background in the novel. The Abbey Dean had received the Hierarch's favor before, so he decided to repay the Hierarch for helping him solve some problems. The Abbey Dean may think that helping the Hierarch can get more benefits and resources, such as getting a recommendation letter or more sponsorship. In short, there were many reasons why the Abbey Dean helped the Hierarch, but the most important one was out of consideration of human feelings and interests.