Obviously, the Guard didn't know who was in front of him. Gael didn't have some unique appearance so that at first glance everyone would realize that he was the Progenitor of Ashens.
He had an insane amount of scars all over his body, but most of the time they were hidden. Only during battle, when Gael needed extra strength, did Gael reveal his scars.
So, the Guard thought that Gael was an ordinary Second Chronicle Ashen that had fallen into their world. This was not uncommon as the Beastfolks were an open race. Anyone could come to their world after getting special permission, which was easy to do since it was just a formality.
The Beastfolks let everyone into their world, as they were interested in learning more about other races and fighting their representatives if they had the chance.
"Hey, what are you thinking about?" Guard smirked, "Have you decided to chicken out and not even make the attempt?"