With mostly upped cards, it is known as Pestal.
Unupped, it's Devtal, for common referral.
It works fine unupped, you just have to tinker with your ideas a little more.
Try something along the concept of the deck I have below...
Hover over cards for details, click for permalink
5uk 5uk 5um 5um 5um 5um 5um 5um 5up 5up 5uq 5uq 5ut 5ut 606 606 606 606 606 606 606 606 606 606 61o 622 622 622 622 63a 8pu
Learn how to use it while playing against AI3. Play like 100 games with it there.
When you are winning comfortably with it, try it in Bronze arena. Give yourself a goal, like at least 10 special spins, before moving on.
After that, and if you are certain you can recognize opposing decks, then give it a whirl in PvP-1.
Human opponents are much more of a challenge, but since you have learned all it's aspects already - you should win more often than not.
Also, you will find that opponents simply leave the game, once they see the first fractal of devourers.
I'm responding to your thread, partly because this is a duo with the Darkness element, and coincidentally, I did participate in the tournament you mentioned.
I did construct a "Devtal" that conformed to the rules - although I did not employ it.
In spoiler below, if you're interested.