Souta knew that Death King was just slightly weaker than the Guardian of the Key in the Multiple Elements Realm. His aura was a little bit weaker but his combat skill was higher than a programmed golem. If the two fought, Death King would probably emerge victorious after a long and hard battle.
This guy could give Souta some trouble in his base form just like how the Guardian forced him to use [Blood Armor]. Souta could easily kill this guy with his release form though.
As expected of the Boss of the Murder Society, one of the strongest organizations in the Hall Plains. It's no wonder that he could send several One Shackled Realm experts to attack the Hundred Face Alliance.