It's all about King Midas...er, Macar, I mean. His ability exiles any creature, even "indestructible" ones, with no questions asked. But to do it, he has to "touch" that creature by untapping...and therefore, must be tapped in the first place. Attacking is the most obvious way to do it, but he's obviously then very vulnerable. So how do we solve that problem?
There are a few ways to do it in the current Standard. The first is by tapping him without it being tied to combat. Black Oak of Odunos and Springleaf Drum probably need no explanation (aside from mentioning that Drum obviously helps you curve into the more expensive cards faster). But here's a nifty rules reminder: what happens when you regenerate a creature? It taps! So with Boon of Erebos and Necrobite, not only can we regenerate Macar if he's threatened--and have him take other creatures down in combat as a result--but we can tap him at the same time! Spiffy.
Since we've got all this tapping potential, let's exploit it by tossing in Pain Seer and Servant of Tymaret, other black inspired creatures with useful abilities. (Forlorn Pseudamma is a little mana-pricey for me, so he's relegated to the sideboard.) And since we could potentially target him with the regeneration spells as well, Agent of the Fates is a nice include, especially for getting rid of creatures with protection from black or that otherwise can't be targeted by Macar.
Last but not least, Nightveil Specter may seem an odd choice. I mean, it's a solid overall creature, sure...but at least on the surface, it doesn't seem to fit. Dig deeper, though, and look at how it combos with Macar (and Springleaf Drum). The gold Macar produces and the mana Drum produces can be any color, so if you exile good stuff with Nightveil, you can play it with relative ease, regardless of color.
The sideboard has a playset of Hero's Downfall for some good old-fashioned kill spells if you need them (probably best as a planeswalker buster here, since enemy creatures SHOULD be dropping like flies with your other stuff), and a trio of Desecration Demons and Lifebane Zombies if the opposing deck necessitates a more traditional mono black beatdown.
What do you think? Other than the Nightveils (which aren't strictly necessary and could be pulled if you need to), the mainboard is pretty cheap and mostly holds up post-rotation. I plan to try it out...will you?