The one who gives the hint

How could this happen? Zen didn't know what he was doing.

The original plan was to let the bishop escape and live, but before that could happen the bishop simply sacrificed his life.

Maybe because he saw Zen with an aura of darkness, making the bishop very alert. Instead of running away and telling the others, he instead tried to fight Zen to the death, that was really arrogant.

The bishop shouldn't act stupid in front of Zen.

There are many ways to fight the darkness in the shadows, and fighting it head-on is never a good idea.

Zen now felt disappointed. It turned out that making such an elaborate conspiracy was extremely difficult. Even though Zen had studied hard to create a grand conspiracy, he couldn't do it.

What is missing? Is the Zen way of thinking wrong?

Hence, even though his plan fell apart, he decided to carry it through to the end. And so, he then put on a disguise mask to disguise himself as the bishop of Muler.