***TRIALS RESPONSE***All comments will assume you're playing versus Halfbloods with your 2nd deck.I have to say, I like what you're trying to do here. Deathstalkers Nightfall is indeed a very potent combination. However, looking at it I don't think it has neither the speed nor the control and healing to deal with them reliantly. Also, 4 Shields is rather overkill.
As Death and Darkness seriously lack versatile, reliable stalling options the only option is to increase your damage output while sacrificing some of the control (note that the overwall winrate might decrease a little, but the wins will be faster thus your reward will increase). With that in mind, I would remmove the Plague, 2 Skull Shields and the Vultures and add a slew of Mummies with another Pillar. I would also switch 1 Nightfall for 1 more Dusk Shield.
Using this I got mixed results, better than with the original deck, but...
Hover over cards for details, click for permalink
52g 52g 52g 52g 52o 52o 52t 52t 52t 52t 52u 52u 52u 52u 52u 52u 542 542 542 542 542 542 5uo 5uo 5uo 5up 5up 5uq 5uq 5uq 8pt
Still not good enoughHowever, I felt that a stalling version would've given way better results, but that just couldn't be done with Death/Darkness.
Hover over cards for details, click for permalink
52q 52u 52u 52u 52u 52u 52u 5l8 5l8 5l8 5l8 5l8 5l8 5lf 5lf 5lf 5lf 5lf 5lf 5lm 5lm 5lm 5lm 5lm 5lm 5mq 5mq 5mq 5mq 5mq 8pk
And then I saw the LightYeah, this i technichally not as much of an improvement on your deck as a different one, but I figured I should post it as well, due to the fact that it keeps the Deathstalker theme and that it yields considerably better results against Halfbloods. The only thing I regret are the new vulnerability to Reverse times, but that is offset by the bigger resistance to shields and the nice Stalling. However, as unupgraded vs Halfbloods is hard, most of the games are really close and the winner is only 1 turn of damage to losing.