Everyone knew who the Underdog’s leader was, Damion Hawk, who would always go walking around in a purple suit and spent most of his time in the nightclub called the Basement. They were such a large gang and a prominent force that they didn’t worry about this fact.
The fact that their leader was known to all in slough. Making them possibly an easy target.
They were also known to be the only gang in Slough that had an Altered. How someone like Kirk was working for Damion was anyone’s best guess and kept a secret even to those in the Underdogs. All they knew was that he was loyal till the very end.