Chương 176: Episode 28: Doing a favor.

His soul capturing ball of the highest degree was in the hand of the tainted mortal!

The three soul workers belonged to the underworld. In the underworld and many other places, anyone that can use the power of blood is considered tainted. In the universe, literally, every powerhouse dislikes the tainted because their powers are too much for them to handle. That's why tainted are recruited by the powerhouses or hunted down before their potential growth maximizes.

The Underworld of this universe had a blood Hell, the master of which, didn't welcome the existence of a tainted being in the universe. As his position as the lord of the hell of blood can be threatened by another blood user. That's why people who can hunt down tainted earns heavy hand rewards from him.