Was it fate that brought him here?
No, that was not it.
'That man is dangerous.' He felt instinctively that he had been eyed by a predator. Although this monster hid his eyes in order to not attract attention, Amir was not the like to ignore such a direct threat to him.
He liked to face his troubles directly instead of making any massive plans, that was the right he had someone strong. His thinking can be arranged for something much better, like his projects or enemies that were at a higher rank than him.
As for these Knights as well as Priest?
They were in an Army Camp, and they were among his men, so the threat to his life was minimal in this place, though the same can't be true when these people act in the field. So he had to make sure, this opponent of theirs was not dangerous.