Yumeko being the gambling addict she was, she was gambling with a weird dark entity one day. Their game had a different price, the loser's head. Yumeko loses this bet and in turn loses her head with a dark spell. Sometime later Yumeko's body walks up to you despite not having a head. What was more strange was that Yumeko's body was strangely acting normal and nonchalant about this. Yumeko waves at you like the real Yumeko would.