Creatures - 21
2 Typhoid Rats
2 Onyx Mage
3 Ashenmoor Gouger
2 Blood Cultist
1 Lyzolda, the Blood Witch
2 Ashenmoor Liege
1 Blazing Specter
2 Hellhole Rats
4 Demigod of Revenge
2 Grave Titan
Other Spells - 17
2 Reanimate
1 Demonic Tutor
3 Terminate
2 Blightning
2 Chaos Warp
1 Heat Shimmer
1 Pain Magnification
3 Wrecking Ball
2 Bituminous Blast
Land - 22
2 Evolving Wilds
11 Mountains
9 Swamps
General strategy: It's an aggro-control deck with more emphasis on the control aspects. Kill creatures, gain card advantage through discard, and finish up with the Demigods, Grave Titans, or Massacre Wurm. Gouger can put out some early damage, and goes well with a turn 4 Pain Magnification or Liege. Blood Cultist because you guys know I like pingers, but this one has a nasty combo with Onyx Mage where you spend 2 mana and tap the Blood Cultist to kill any creature. My only complaint is with the way the game portions out the mountains and swamps for this deck. I have 3 mono-red cards and any multicolor cards only require 1 red mana. Meanwhile, I've got more mono-black cards, Grave Titan with a double black cost, and yet the game gives me 11 mountains and 9 swamps. Those number should be reversed. It hasn't been too much of an issue, as long as you search for swamps most of the time with the Evolving Wilds.
Typhoid Rats - He allows you to hold off problematic hexproof creatures like Dungrove Elder and Geist of Saint Traft. If your opponent wants to spend removal on it, that's fine, it's a 1 mana creature, and that's less removal they'll have for your bigger and better creatures.
Vexing Devil - It has some nice synergy with Pain Magnification, but that ended up being the only reason I was running it. Otherwise, I don't care to spend a card and do 4 damage to my opponent in the early game. If you want to go a bit more aggro, definately include these. You could replace the Massacre Wurm and something else for them. And they do make a nice early game combo with Reanimate.
Pain Magnification - This card has been pretty decent for me. Drop a Gouger on turn 3, then Pain Magnification on turn 4. Now watch as your opponent shifts the way they play, making unfavorable blocks to avoid discard. Blightning now discards 3. Hellhole rats might now discard 2 if they pitch a 3 mana or higher card to it (which, they might be forced to do). Add in the Liege and now attacking with the Rats and Specter become even more dangerous to your opponent's hand, and their haste becomes more handy too. The Demigods now swing for 5 in the air with haste, and get a bonus of discard.
I think the thing that makes Pain Magnification stand out is that it's an enchantment, so it will sit on the board unless the opponent can remove it. It's always a threat. Blightning and Mind Rot discard 2 for 3 mana, and they're both great cards. Heck, even if I only get 1 activation from it the whole game, it's still worth it because of how it changes my opponent's playstyle. But the fact that it's an enchantment means that when my opponent gets to topdeck mode, they're still forced to play every card they draw or else risk discarding it. This deck doesn't have card draw outside the situational Lyzolda, so to gain advantage you want to keep your opponent's hand empty.
Blightning - Never a dead card. I like to use it when my opponent only has 2-4 cards left in their hand, that way you know you'll hit something good.
Terminate/Wrecking Ball/Bituminous Blast - Instant speed creature removal is good, as is the cascade on the Blast.
Rockslide Elemental - It does combo nicely with Onyx Mage, but I can't find room for it. I could replace a couple of the Gougers, but Gouger goes better with Pain Magnification, whereas the Elemental doesn't have an immediate impact alongside Pain Magnification. It's a little slow to build up. For those reasons I decided not to include it.
Deathbringer Thoctar - 6 mana for a 3/3 doesn't impress me. It takes some work to get going. Sure, it goes well with Onyx Mage, but I don't include cards just because of situational combos, the cards need to do well enough on their own for the purposes and goals of my deck. This is why I cut Vexing Devil, and why I cut Thoctar. For 6 mana, I want finishers that have more immediate impact, not a 3/3 that needs maintenance.
Defiler of Souls/Malfegor/Rakdos the defiler/Kaervek the Merciless - These cards are very Rakdos in feel, and I'm glad to see them here. However, they're only situationally good, and sometimes they can backfire (Rakdos). Meanwhile, Grave Titan has proven itself as a good solid finisher for control decks in Grave Whispers and Obedient Dead, and that hasn't changed here. Combine this with the 4 auto-includes of Demigod of Revenge, and there's just no room for these guys in the finisher package. It's not that they're necessarily bad, it's just that there's better options.
Massacre Wurm - It's worth using if you want another big creature, but you may want to run 23-24 land if you include any more 6+ mana cards. The triple black cost is only occassionally an issue, as double and triple black mana costs become negligable at the 6+ mana cost. If you have 6 lands, it's reasonable that at least 2-3 of them would be swamps, especially if you're seaching them out with Evolving Wilds. Defiler of Souls is also worth it instead of the Wurm, both of them have nice removal effects, even though each is a bit situational.
Din of the Fireheard - I really like this effect, but 8 mana is just too much for a deck without consistent card draw or acceleration.
Bloodchief Ascention - I don't really care for cards that don't have an impact on the board (Pain Magnification does have its subtle impacts). And in this respect I find it comparable to Liliana's Caress from Grave Whispers. Yeah, it can do damage, but it won't affect the board position, and won't help you come back from a losing spot. For the aggro build, it's slow to build up, but on the positive side, this does give you a non-creature win card.
Chaos Warp - It's a nice answer to enchantments and artifacts which this deck has no other way of dealing with once they hit the board. It also has some niche uses to counteract Mind Control, Rite of Replication, Bribery, and Rise from the Grave, while possibly giving yourself a permanent. The downside is that it can give your opponent something big and make your problems worse, but more often than not, it'll turn up a land, a 4 or less mana permanent, or a nonpermanent card, since decks aren't generally running a lot of big 5+ mana bombs.
Heat Shimmer - Another card with a lot of utility uses. Use it on Hellhole Rats or the Specter to cause more discard, then sac the creature to Lyzolda's effect. Use it on Gouger or Demigod to push damage through, or a Grave Titan to get a massive amount of zombie tokens. It goes well on your opponent's creatures that have enters the battlefield effects, especially other titans. And there's also the ability to copy your opponent's legendary creature in order to remove it.
Stabbing Pain - There are a lot of 1 toughness creatures in this format, but this deck already has Blood Cultists and lots of solid instant speed removal. That leaves Stabbing Pain on the sideboard for matches like goblins and peacekeepers.