Fire Emblem Heroes has grossed an estimated $452 million worldwide.
I was a one of the pioneers on chartz who advocated Nintendo must seriously enter the mobile market as there was so much money to be made. So far they've only really dipped their toes into it but are already seeing big returns. Now they need to double down and up their mobile support even more. There are billions to be made.
Now on these figures Pokémon go revenue isn't factored. Otherwise FE wouldn't be at such a high %.