The long-haired King couldn't really understand what had happened. Actually, he could, but failed to realize how.
For all intents and purposes, the King had blocked Lord Blind Sword's seemingly non-existent blade. He saw its intent clearly and could interact with it, even harnessing it to reflect it at his opponent.
However, despite blocking the blade, Lord Blind Sword's attack had still risen toward the sky, cleaving the darkened area and the burly King in half.
As for how Lord Blind Sword had achieved that, the long-haired King could only guess, his instantaneous conclusions condensing into two possible alternatives: the Royal Guard could launch attacks without relying on his blade, or what the King saw wasn't the entirety of his sword.
In both instances, it was evident that the long-haired King couldn't completely stop Lord Blind Sword. He probably didn't even have the time to learn more about his ability, forcing him to change his battle strategy.
