This deck is easily my favorite I've built and by far my most interesting. Considering it's my 7th that's not the best endorsement, but I think it's pretty good. This deck was originally created because I thought Ravenous Demon was pretty cool, from there it just snowballed into something that helped me get the edge on my much more experienced friends.

It's based around sacrificing creatures and through Dictate of Erebos forcing others to do the same, leading to quickly emptying the battlefield of enemy creatures. But even without Dictate you can still make people fear you using Skirsdag High Priest Morbid ability to pump out 5/5 flying demons for every creature you sacrifice. Xathrid Necromancer is there to make sure you never run out of creatures and to help you make an army if you've got more than one out. Make people sac their creatures also lets you hit them with things like my 9/9 flying trample Ravenous Demon.

But one of the best cards in this deck is Vizkopa Guildmage. That's my one turn game winner if you have Coat of Arms out and Disciple of Griselbrand. Coat of Arms turns all of my humans into monsters, easily AT LEAST 7/7s usually, then just activate Vizkopa second ability and start sacrificing these monsters with the Disciple. I start gaining massive amounts of life and opponents start losing that much life. Easily a one turn multiple kill combo. 

If you have Ravenous Demon out with Vizkopa just activate Vizkopas 2 abilities and deal 18 damage in one hit to one player and 9 damage to all other players. If you have coat of arms or Swift justice out that will give you the buff you need to kill one opponent easily in one turn and deal at least 10 to others. With Swift justice you can kill someone for just 4 mana using Ravenous Demon and Vizkopa. (I might add more of those.)

Harsh Sustenance provides a surprise kill with Vizkopa as well. Because of Gather the Townsfolk and Increasing Devotion, by the time I draw Harsh Sustenance I can use it to kill a single opponent and deal significant damage to all others with Vizkopa. 

Pretty much as soon as you get Vizkopa Guildmage out, it won't be long before you can kill everyone in two turns. But even if you don't you can do it the old fashioned way through heavy damage with Demons and an army of Humans and Zombies because nobody will be able to block due to you making them sacrifice their creatures with Dictate of Erebos. But even without the Dictate you should be fine with the aforementioned army of Demons, Humans and Zombies and some help from Brave the Sands.

Sign in Blood is extremely useful for getting to the cards you need faster and the loss of life is usually negligible because you will be gaining massive amounts back through Vizkopa and the Disciple.

The only thing you really need to worry about with this deck is Ravenous Demon and running out of humans. Because if you do, Ravenous Demon starts doing 9 damage to you and tapping itself at the beginning of your turn. You can avoid this by sacrificing the more important creatures if your out of 1/1 human tokens, but that's why Undying Evil is there, to make sure you never run out of humans and to provide a safety net for your creatures in critical moments. Worried about losing a creature in an attack? Don't be! With Undying evil it will just come back stronger (and if you have Dictate of Erebos out opponents will have to sacrifice a creature as well).

This deck is surprisingly cheap for how strong it is, and I easily murder my friends much more expensive and shiny decks with it. The most expensive card is Coat of Arms which I got from my local Magic store for $8 but it is definitely worth the price. I'm probably going to buy a second for this deck and everything else is ridiculously cheap so you won't be spending much considering what your getting. Honestly for how good this deck plays it is ridiculously cheap.

DId I mention this is easily my favorite deck?

(Obviously this deck is not standard since my friends and I don't play standard because we aren't pussies and we are far too lazy to keep up with all that.)