How to get evil hero dark gaia at 12400 atk???????????

this is my fun deck that can be very deadly sometimes.
https://i.imgur.com/7JSCNJq.png

But how to get evil hero dark gaia to 12400 atk???
its simple:
*first you use dark calling banishing valkyrion and grapha and dark gaia's atk goes 6200
*than megamorph rises his atk to 12400 but to do that your lp must be lower than your opponents and upstart goblin can help or your opponent.

thats my otk dark gaia deck.Hope you liked it

seems cool, but a bit slow. I`d love to play against it

it isnt slow cuz you can win with dark worlds too