I'm looking for a CN where the MC's primary cultivation technique/ attack techniques/dao is darkness or based upon the dark attribute.
LORD SHADOW, but Mc is to much emotional so I can't say it's dark story but he does use shadow/death elements.
Warlock of the Magus World and I think you should go filter and find all of the cultivation novels lol
I can't say it's "primarily", but Heavenly Jewel Change's MC uses the darkness (and demonic) element a lot.