Protection, damage and Leyline of Punishment
The Champion will end up getting destroyed by the Anger of the Gods because of this rule.


  101.2. When a rule or effect allows or directs something to happen, and another effect states that it can't happen, the "can't" effect takes precedence.


So you have the Champion saying damage can be prevented, and the Leyline saying it can't be prevented so it isn't prevented.