Oh, he didn't do so himself. He was quite clear on that point. Apparently they were scattered so he would no longer have access to his powers - and having seen him with full access to his powers, I can hardly blame the person who did it. [ Says the guy who now has full access to the very same powers, without a trace of irony. ]

Tokyo, you say? We summoned a demon in Tokyo once. Lovely city. Would have been better with at least two fewer demons in it.