Falling (堕とす (おとす), Otosu) or Dropping is the ability to summon from the Other World. It is the ability inherited by Enyou Hiizumi's branch of the Hiizumi clan. The phenomenon is also seen to occur naturally since the emergence of the Nanagou. It is the opposite of tuning.
People who become possessed by souls falling from the other world they become known as fallen.