The possibility of the former is very small, and he doesn't think the head would be that formidable, so there's only one possibility left.
A glint of insight flashed in Su Changxing's eyes: "You're not from this world, are you?"
The head laughed: "When did I ever tell you I'm from this world? I'm a great True Knower; how could I be confined to a mere world?"
Su Changxing thought for a moment: "But you only have a head. If it weren't for me, you'd be trapped in that room."
The head said proudly: "Then how do you think I got here from that room?"
Su Changxing gritted his teeth; talking to this head was always aggravating, and then he asked: "Which world do you come from, the technological world? Or the magic world, or somewhere else?"
The head mysteriously said: "You guess."
Su Changxing said: "Judging by your zombie appearance, it should still be the technological world; a world full of extraordinary power shouldn't fear such zombies."
