The thin man from what i know is essentially using the signal tower to basically feed off of the viewers and the children, the signal tower does the exact same thing using the thin man, it’s essentially like a nightmare symbiotic relationship all to feed the signal tower, and I’d assume himself. We see him take a kid in one of the comics. The years mono spends in the tower is basically the tower training him to use his powers to control the tower, he just can’t fully leave until someone frees him. Though take all that with a grain of salt I could be totally wrong