Anyone know the title of this bl manhwa?

To start with, it's a guideverse and the characters' hair is black.

The guide was tested to see, if he was compatible to an esper. The result was that he was compatible to all the esper, so this resulted to him being exploited by all the esper.
One time he stumbled upon a basement and saw an esper lying down with a guiding machine (I think), he guided that esper, then the next day that esper woke up, and begin finding the guide. That esper was known for being cruwl and strong. When he found where the guide was, he offered to be his exclusive esper. And he will not allow other esper to exploit.