Even though at the end of the day we're relying on staples such as Blood Artist, Bloodchief Ascension, and Gray Merchant of Asphodel to secure our glorious triumphs, the whole fun of this deck is using Maha to hobble our opponent's creatures toughness and wipe the entire board (with the exception of our creatures whenever we can help it) with rarely used, low mana cost -1/1, -2/-2, and -X/-X spells turn after turn.
-1/-1
Cower in Fear, Make Obsolete, Plague Mare and Suffocating Fumes
I dare you to tell me you've heard of any of these cards before...well maybe Mare was on my radar. Let's play all these effective and efficient three mana cost spells to give all of ONLY our opponent's creatures -1/-1 until end of turn. Cue Maha picking at the scavenged corpses of our enemies once mighty fallen soldiers. Holler to Suffocating Fumes for its cycling ability in a pinch.
Curse of Death's Hold
An aura curse that causes the biggest threat of our own choosing's creatures to have -1/-1 as long as the enchantment remains on said player. Great as it's a curse that targets and stays directly on our opponent, as opposed to a normal aura enchantment that would fizzle and die with a creatures removal (we do a bit of creature removal in this deck). It's also a great lock on any of our cursed opponent where if they can't remove Maha, they can't cast any creatures that don't enter with +1/+1 counters. Downsides, its high 5 mana cost and fact it only targets one player. Another prospect to be removed in favor of lower mana -1/-1 or -2/2 spells, but recall, this one is all about the forgotten, dust covered cards in the bottom of the cardboard bins at your local LGS getting a chance at some glory for once.
Kaervek, the Spiteful
We like Kaervek because he can stay on the battlefield with Maha so none of our opponents can cast creatures without them immediately falling on their own swords and heading to the graveyard. Getting these two out together causes to draw out some our opponent's targeted removal spells towards Kaervek instead of Maha, especially if we're already showing cards like Netherborn Altar. Always good to get them out. Bonus we can reanimate Kaervek if needed.
Nausea and Soul Snuffers.
-1/-1 spells that target ALL creatures. Yes, ours too. Note that Soul Snuffers places an actual -1/-1 counter on each creature and is not a -1/-1 status effect like the others. Can pair nicely with Spitting Dilophosaurus's ability to make creatures unable to block. The only two creatures we run in our deck with 1 toughness are Blood Artist and Orcish Bowmasters, but be aware these two spells will take them both down as well if on the battlefield.
Night of Souls' Betrayal
One of our MVPs in the deck, hands down. With Nights and Maha on the battlefield, any single creature our opponents cast without counters are instantly killed when they enter the battlefield. Same total creature lock out effect we get with Kaervek, the Spiteful except on a harder to remove enchantment. This can be absolutely brutal on our enemies. The joy of watching our opponents continue to cast creatures and send them to their instant doom until we politely remind them how the effect works is priceless.
Pestilence
Not a real -1/-1 spell, but its direct damage to opponent and each creature ability fits into this section best. One of our best enchantment pieces for decimating our enemies toughness 1 creatures. It's great that we can get it out early, before Maha takes flight and then use its ability for only one mana once she has arrived to wipe our opponents board. It's also great that it's not an upkeep trigger, but an activated ability we can choose to stop using if need be. Also another one of our great finishers in the deck for our opponents when we get them down to low health totals.
Screams from Within
A unique, priceless effect in our deck. Although this card only targets one creature initially with its -1/-1 ability, with Maha flapping around the battlefield this is an instant wipe of all our opponent's creatures loop. Simply target a new, crippled toughness 1 creature with Screams from Within each time it is returned to the battlefield on the previous creature's death and enjoy the echoing shrieks of your opponents all around you.
Spitting Dilophosaurus
Dun DA dun dun dun. Dun DA dun dun dun. Da DA dun dun dun. DUN DUN DUN. Welcome...to Jurassic Park or possibly Seinfeld. Whichever you prefer. This is a great new prehistoric hit, we slay any creature of our choosing on our dino's ETB ability and every turn it attacks. Although we don't have a ton of higher P/T creatures to swing with, don't forget this hisser's ability to make your opponent's The Ur-Dragon or other pesky, flying blocker, simply unable to after just one -1/-1 counter added. Who know's maybe someone else is playing proliferate as well.
-2/-2
Cry of the Carnarium
Although its higher -2/-2 effect will take out a few of our own weakest creatures if in play, Carnarium is a must include for its exile ability. Even if our drain happens to help us often bypass fog effects and Spore Frog loops, we want to have at least some options of dealing with other's graveyard abuse if necessary. Bojuka Bog and Final Act are our only other means for this, so if you have other -/- cards in hand, be sure to use them first and save Cry of the Carnarium as a last option in case you need to utilize the exile effect.
Massacre
It took someone at WOTC a long time to figure out how they could best ruin two magnificent new arts (Massacre and Mogis, God of Slaughter with this trauma inducing comic sans font Secret Lair. All grievances aside, and it isn't easy for me on this one, we like free mana spells. It just puts a little pep right in our step. Conditional on an opponent running white in their color identity and having a Plains on the field, we ourselves need a Swamp. If you don't have a Swamp by the point you're trying to cast this, you have bigger issues to worry about that being stuck with a 4 mana cost -2/-2 spell. The often satisfied requirements for the free mana cost in most EDH games makes the conditionality worth it.
-X/-X
Black Sun's Zenith
This peak is well worth reaching for in our deck and the flavor of a Black Sun with our It Feathers Night "Black Death" energy is mwah. Great that it's another spell that puts actual -1/-1 counters on creatures (Spitting Dilophosaurus). We're almost always aiming to cast this for just a single 1 X mana cost so we can keep our bird alive and in the air while our prey melts around us. Then shuffle it into our deck and do it all over again.
The Meathook Massacre
One of our best -/- spells in the deck that could have also been listed under our life drain / gain category. Similar to Black Sun's Zenith we want to cast this for a single 1 X mana cost with Maha circling the battlefield. Wipe all of our opponent's creatures and add yet another taxing life drain / gain enchantment ability to the battlefield at the same time. Enjoy the same turn triggers on your enemies creature's deaths to begin with. Pairs excellently with our Bloodchief Ascension.
Toxic Deluge *f-etch*
Another absolute banger of a -/- spell in our deck. We gain a lot of life in this deck and don't mind often dumping a good portion of it into life cost activation spells and abilities. Deluge is no exception to this. We can cast this one for just a single life point with Maha out like our Black Sun and Meathook, but Toxic Deluge *f-etch* is great also for being able to kill large P/T enemy threats when Maha is removed or we have a slow ramp game. Deluge is another one to try and hold onto if you have other -/- spells available to use first and a great one to draw and keep in an opening hand.