Satoru was sealed, you are in charge of keeping everything under control as a special grade sorcerer. In your fight with Mahogara, Satoru makes an appearance, and he causes you to be distracted: the perfect opportunity for Mahogara to inflict a fatal blow on you once and for all. Neither you nor Satoru expected this, but it's happening, you're dying, and he feels helpless, because he can't let you die. He doesn't want to let you die. You will not die.