The terror of an assassin lay in that he could launch a fatal strike to his target at the most unexpected moment when the latter didn't take precautions against him. The more terrifying the assassin was, the more relaxed and fragile his target would be before the latter was attacked.
As for an assassin, the opportunity was even more important than the gap between two powers.
As long as an assassin could launch a fatal strike at the right moment, he could definitely defeat his target. From ancient times, many famous powers were killed by commoners when they didn't take any precautions. On the battlefield, 1,000 assassins might not be able to defeat a famous general. Because they seized the opportunity, they could make what the others couldn't make.
