People forget how Arwin lived before he became where he was. I guess theyll eventually show us his background story in the future. But Latte already mentioned some important things about Arwin from the earliest chapters. We might think he's an asshole who only nice to the person he likes. But think about it, he only does kill people who threatened his life. It's a way of him surviving before and maybe still. A lot of people trying to kill him before because he was powerful and the way to survive was to kill. It either be killed or kill. Remember how in the original story, he took over the tower. Not to become a tyrant. But he removed the corruption that it has. He's always been a common people side. Anything he deem corrupted, he'd fix it just like he did in the magical world. He gave those people a living, made them better magician, etc. So I don't see Arwin as bad as people think he is. He might say he'll kill someone but he hasn't done it, has he? But think about in his stead, someone who is knowledgeable and powerful as a magician, he needs to let people know that he's not easy to get rid of. A lot of people wanted him dead, you know. Arwin only took care of people who are greedy and corrupted. He never hurt someone physically without a reason.