Water Monkey King - Please help me find a reason to use him

Hello everyone,

I've just got my next nat 5* - water mk. The thing is his skillset is not that useful, and he's way too little to fight in PVP.

Do you guys use him above any other monster in specific circumstances ? How I could find a place for him ?

In my opinion his atk should be increased to 900 and he would be viable..