The effect of “Ebon Magician Curran” is a Trigger Effect that can be chained to.
Count the number of monsters on the opponent’s side of the field when you resolve the effect of “Ebon Magician Curran”, not when it activates.
If “Ebon Magician Curran” is Special Summoned during the Standby Phase while “King Tiger Wanghu” is on the field, both Trigger Effects activate immediately and form a chain.