The plot is shit. I understand that he wants to kill the Demon King, but he sacrifices demons and humans who are kind, admire him, and are loyal to him. Rubbish.
To be fair I think it shows just how insane he is, and how far he has fallen attributed to the fact that he killed his family wrongfully and his brother, who he thought hated him, died protecting him and still loved him all this time
The plot is shit. I understand that he wants to kill the Demon King, but he sacrifices demons and humans who are kind, admire him, and are loyal to him. Rubbish.