"Appearing in front of us now... it was the last mistake you will do in this life!" One of the knights spoke in a tone filled with hatred, then broke the defensive formation and charged toward Robin holding his spear with all his might, while the rest remained in their places in anticipation of another attack from the guy who sent those fire balls!
Physical strength is everything in this world, and with physical strength as none existence as this peculiar human, he certainly didn't launch these attacks himself, He has to have a partner or some external methods that he used...
This is the best chance to get rid of him before focusing on whoever attacked them just now, but they still have to be careful of what is around them.. the peculiar human wouldn't have shown himself like that if he didn't have a plan!