When Evan said that the portals appearing across the Earth had nothing to do with him, many hunters didn't believe his words.
Evan could see that they did not believe him, but he didn't care about their doubts.
Even if they didn't believe him, it wasn't as if they could do anything to him. However, to ensure that they wouldn't do anything foolish or try to withhold information from him, Evan told them that as long as they provided the information he needed, he would help them clear out the high-level monsters currently filling the Earth.
Most of the hunters were shocked when they heard Evan, but when they remembered his power and the fact that he could even control the powerful black monsters that had captured the Glacifern people emerging from the portals, they also believed that it wouldn't be difficult for him to help them clear the high-level monsters.