There is part 3 for the interview with Hokazono:
The Part 3 of Hokazono-sensei interview/tips: How to create enemy characters
Question: In 'Kagurabachi', presents many charismatic enemy characters such as Soujou and Sazanami Kyoura. Please tell us what you keep in mind when creating enemy characters.
Answer: "For enemies who confront Chihiro, I want them to hold a conviction that is opposite to Chihiro's but unwavering. When their convictions clash, it makes the enemy, who does not waver, appear more compelling alongside the protagonist as they overcome their own doubts. I also want the enemies to be reckless in their commitment to their convictions, fighting to the death."
A thorough analysis of the enemies in 'Kagurabachi'!! (With Soujou as an example)
Point 1: Soujou instills a strong conviction! He says: 'Youtou are the ultimate killing weapons!'
Soujou deeply admires Rokuhira Kunishige, the creator of the Youtous. He is an enemy character who displays a fierce and intense belief.
Point 2: Have their convictions clash with the protagonist!! "Why do you wield the Youtou?" A clash of opinions with Chihiro!!!!!
The cursed swords exist to destroy evil and protect the weak," says Chihiro, clashing in opinion with Soujou. Even as an enemy, his unwavering conviction is captivating...!
Point 3: Relentless in his beliefs!!!! "Even after sustaining a fatal injury, he continued to seek the power of the cursed sword until the very end...!!!
Even after being slashed by Chihiro, Soujou desperately sought to obtain the power of the cursed sword until he was completely exhausted...! Even as an enemy character, if his seriousness about his beliefs comes through, he looks really cool!"