>>54517688Because it really shouldn't have been made in the first place, and only existed since anime mandates wouldn't let Ash have a Mega Evolution due to the "aside from Pikachu, Ash can only use new Pokemon from the new games" rule when Kalos only had Mega Diancie after ORAS, but that conflicted with the "Ash can't have a Legendary or Mythical Pokemon" rule.
Thus, the anime team conceived Ash-Greninja as a compensation, failing to see the ramifications of giving Ash a Special Snowflake "once in a gorillion years" form of Pokemon when he was STILL destined to lose the Kalos League Tournament due to the "if Ash wins a League Tournament, the anime has to end" mandate.