In the end, ziyu won. Now he's going to send Siduo to join him in hell. Siduo, of course, is a reference to linxu's shadow, which was created by the teacher in order to separate himself from his memories of the battle with the koi clan. The teacher explains that siduo is like the shadow that he separated from himself back in the day, and that he killed it with his magic when he separated his emotions into his shadow. The only difference between the two of them is that Siduo chose to kill the shadow, while the teacher chose to save the shadow. So, Siduo is just like the teacher, right? Siduo says that he wants to kill everyone, including the teacher and the teacher's daughter, because he wants revenge on s/he chose to betray him and save linxus. But Siduo reminds him that they still have time to save him.