Near the end of the movie, instead of smacking Credence, Grindelwald realized he was the obscurus and took him away. He gave him anything his heart desired to keep him his devoted pet monster.

Except, by the time Grindelwald is captured, all its done is make Credence a spoiled brat.

(My kingdom for Graves or Newt putting Credence over his knee and giving him a (sexy) spanking)