User blog comment:Godzillavkk/Kingdom of the North vs Northern Water Tribe/@comment-11361577-20190522211744/@comment-11361577-20190523003935

Warging can be done on physcal beings yes but the two fishes aren't just fish they are littraly the repensentation of the moon and water. Warging is difficult already when you do it on a human doing it on gods would be impossible.

Also I am not sure if you are talking about Bran littarlly warging the moon and not Tui, but if you are that is just plain rediciouls. Even if he did what then? The only way when the water benders would loose their bending would be during a lunar eclipse you can't just become the moon and tell them not to bend.