You have to say that even those people got shocked by his sudden appearance, but then they calmed down and started to tell.
"Our ruler wanted to know why you are helping these people. Did these people hire you? If that is the case then we could give you more resources, with that you just need to kill all of these people."
That person or you can say the Messenger from a ruler said that to Alex. Right now if you look at him then you can say that he was hiding his face so nobody could tell about his identity. This is also one of the reasons those people thought that these human fighters hired him.
Right now if you are able to look at Alex's expression then you can see the shocking expression that he has on his face.
"Haha…"