Well, the muse had some free time and granted me an idea, not much i know could do better. Here is it:

Richard one day tries to contact his "humanity" by slaughtering a nice, overcrowded and happy monastery full of do-good-ers. His "work" gets more and more entertaining as he fooshes with delight the priests, when someone "mundane" decides to visit Richard. An female entity with a strong appetite for souls and pain, a very special Succumbus.

I am going to spin some words and come with an interesting poetry, meanwhile while i gather the words, feel free to comment.

One day Richard bored to death
Thought to act against his fate,
So he journeyed to The peak,
To kill, to slaughter, to find belief...

I'll continue to add.

Is a succumbus a type of Succubus?

Yes, i thought by spelling it different gave a certain identity to it until i come with a sounding name .