Both TheOnlyRealBeef and SnoWeb are correct. If you're just going to bury your devourers, then the earth mark is most likely not worth it. It will most likely slow you down and not provide much benefit in the long run if your devs are buried or not. But if you decide to include earthquakes, then burying your devs will most likely become a worthwhile investment since they will be able to drain the quanta that your earthquakes were not able to stop from generating.
If you want to go the Earthquake route, a basic deck like this would be perfectly good:
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593 593 593 593 593 5um 5um 5um 5um 5um 5um 5uo 5up 5uv 5uv 5uv 5uv 5uv 5uv 606 606 606 606 606 606 606 606 606 606 606 8pm
Basic darkness and earth duo, all your darkness creatures get added protection. Devs get to burrow, and your gargoyles are buffed by 20hp. Not so frail now are they? xD
But if you want to stay mono darkness, you're looking pretty good
. I may cut out a few dragons once its fully upped, resulting in something like this:
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7t4 7t4 7t4 7t4 7t4 7t5 7t5 7t6 7t6 7t6 7t6 7t6 7t6 7t8 7t9 7t9 7ta 7ta 7tb 7tb 7td 7td 7td 7td 7td 7td 7um 7um 7um 7um 7um 8pm
More vampires allows for the slower start that pests create