Derg!

He's actually true neutral. Part of his lore is that in order to tame the demon lord he had to go to the realm of demons. The secret to taming a demon lord came from befriending a lesser demon that had the knowledge but not the power to do so and in befriending the lesser demon it turned his whole concept of good and evil upside down (mankind is good, demons are evil kinda thing), so in his travels one of his main goals is to find out what really is good and what really is evil. He keeps a notebook that he writes in abyssal his findings, calmly observing everything and only interfering when it affects the party itself. When we're at the end of our campaign I'm going to reveal to my friends in the campaign what is written in there for some laughs, especially since some of it came about by some hilariously low rolls (a 2 on persuasion and a 1 on perception against that persuasion being a prime example).

Actually no. The demon lord is constantly whispering to him trying to take over his mind. If Hans loses, he loses his mind. I forgot the other part of the lore from above. His master wasn't a kind master. One of the reasons why his tail is permanently scarred is because for punishment his master would cut off the tip and feed it to him (also why he attacks anything that touches his tail). So he saw the evil in mankind and the good in demons, which is backwards from tradition and why he's trying to find the answer.

So, Hans is Neutral, but the Demon lord is evil? Hans couldn't just settle for that lesser demon he befriended?