Sometimes in this world, some people were blessed. They weren't blessed in a religious term like those who use holy power but blessed in another way. Those people have a certain talent in a weapon, and when they were using this weapon, their growth would be insane.
They would have something like an innate talent that would show them what to do and how to react in certain situations. And even sometimes, when they were so engrossed in a fight, they would do things without thinking, a little like it was instinctive for them.
And Eden did just that.
He wasn't even aware of what he was doing earlier. He just knew that he won.
How?
He didn't know. But seeing so many arrows on the ground, he could only guess that he had sent arrows after arrows to Elric and that he didn't let him do anything.