Heh, I've added the new Bolas's Citadel into my dedicated Dralnu Storm deck. I'm really looking forward to giving it a test spin sometime soon to prove why Dimir is da best. It opens up an entirely new combo line with Sensei's Divining Top and Aetherflux Reservoir, two cards I was already playing in the deck. It now feels like my Dralnu Combo deck is about as lean and optimized as it can be.
I don't think you'll be disappointed with Nezahal. I keep tabs on the cEDH reddit and they've almost universally switched from Consecrated Sphinx to Nezahal, Primal Tide. Nezahal's trigger is a MUST whereas the Sphinx is a MAY; Nezahal can't be countered, which can sometimes be relevant; Nezahal protects himself with an ability that he can help fuel; and the max hand size modifier is great against opposing Jin-Gitaxias' and ensuring a stronger Control plan. If possible, I think it's totally worth running both, since the power of the Sphinx cannot be denied.
My brother has a really annoying Muldrotha deck too. Suffer the Past could be useful to you as a way to Exile the Muldrotha players 'yard with a synergistic card. As for myself, I usually play try and race the Muldrotha player, as I know that they'll probably beat my long-term game given enough time.
Tendrils of Agony is a great card to pad the life total. It's far too easy to cast it, gain 14-20 life, and then flashback it via Dralnu and kill a player with its flashback copy.
EDIT: In other news, the new Lazav is a really cool card. I wonder if it has any use in this particular configuration or if he's better as the Commander for his own style of deck?
Nezahal, Primal Tide, depending on the decks that you're playing against, is sometimes even better than the SPhinx. The ability to protect itself for free is really quite awesome. There used to be a heavier Storm/Spell-slinger presence in my meta, which has tapered off pretty sharply, but there were times when Nezahal drew me 10+ cards in a turn cycle. When an opponent is chaining together Tutor effects, casting enchantments, and recurring the 'yard in one turn, it was easy to draw an overwhelming number of cards and often win on my next turn.
And sometimes the 7 power it boasts is not bad either for going down the beat-down route.
However, it really depends on your meta. If there isn't a high presence of non-creature spells being cast in your meta then the Sphinx is ultimately better. It may not be a bad idea to run both. When I played Tasigur Reanimator, before I switched it to Tasigur Flash Hulk, I found that Jin-Gitaxias drew me too much attention and started affecting my ability to interact. I think that Nezahal might be a more politically palatable Reanimator target that comes with some solid card draw without wiping out your opponents' hands. Otherwise, I think cutting It That Betrays is a good choice.
Wanted to chime in as to a Streamlined Dralnu Combo list that I've been running to great success. The List is spoilered below and it's one of the most efficient decks I've played (excepting my Teferi list, list in my sig). The explanation for the deck is somewhat lacking on my thread there, but I'm happy to answer any questions.
If you're going to diversify your win conditions, I think that adding in Tendrils of Agony is a really good way to go in comparison to the Desire. I play a couple of important X spells in my list and I don't want them exiled or cast for 0 when I'm desiring off of a high Storm count. Do note that this is purely my preference, as the Desire is a fantastic card for a dedicated Spellslinger deck. Do note that my Dralnu list is all-in on the Paradox Engine synergies and eschews the Reanimator package that your list plays with, Jenn.
Here's my Devastating Dralnu Destructor Fish-Bowl Laser Deck of Death:
One Reanimation target that seems super strong is the new-ish Nezahal, Primal Tide. I'm not sure how relevant he would be in your meta but in a higher tier meta the Plesiosaur can draw an absurd amount of cards with built-in protection. Usually, there's a higher concentration of non-creature spells being cast for more competitive decks, so the Plesiosaur would get some fantastic mileage while also being a relevant attacker. Pitching cards for his Blink ability (for protection) is never a bad thing to do with Dralnu.
And besides, it's a Dinosaur. You're playing a Reanimator deck. Reanimators bring back extinct things. Dinosaurs are extinct things. You should be Reanimating dinosaurs. The end.
UB Dralnu, Lich Lord
RBW [Primer]-Kaalia of the Vast
BUG [Primer]-Tasigur, the Golden Fang
GWU [Primer]-Arcades, the Strategist
WUB Primer-Aminatou, the Fateshifter
UBR Nicol Bolas, the Ravager
My brother has a really annoying Muldrotha deck too. Suffer the Past could be useful to you as a way to Exile the Muldrotha players 'yard with a synergistic card. As for myself, I usually play try and race the Muldrotha player, as I know that they'll probably beat my long-term game given enough time.
Tendrils of Agony is a great card to pad the life total. It's far too easy to cast it, gain 14-20 life, and then flashback it via Dralnu and kill a player with its flashback copy.
EDIT: In other news, the new Lazav is a really cool card. I wonder if it has any use in this particular configuration or if he's better as the Commander for his own style of deck?
UB Dralnu, Lich Lord
RBW [Primer]-Kaalia of the Vast
BUG [Primer]-Tasigur, the Golden Fang
GWU [Primer]-Arcades, the Strategist
WUB Primer-Aminatou, the Fateshifter
UBR Nicol Bolas, the Ravager
And sometimes the 7 power it boasts is not bad either for going down the beat-down route.
However, it really depends on your meta. If there isn't a high presence of non-creature spells being cast in your meta then the Sphinx is ultimately better. It may not be a bad idea to run both. When I played Tasigur Reanimator, before I switched it to Tasigur Flash Hulk, I found that Jin-Gitaxias drew me too much attention and started affecting my ability to interact. I think that Nezahal might be a more politically palatable Reanimator target that comes with some solid card draw without wiping out your opponents' hands. Otherwise, I think cutting It That Betrays is a good choice.
UB Dralnu, Lich Lord
RBW [Primer]-Kaalia of the Vast
BUG [Primer]-Tasigur, the Golden Fang
GWU [Primer]-Arcades, the Strategist
WUB Primer-Aminatou, the Fateshifter
UBR Nicol Bolas, the Ravager
If you're going to diversify your win conditions, I think that adding in Tendrils of Agony is a really good way to go in comparison to the Desire. I play a couple of important X spells in my list and I don't want them exiled or cast for 0 when I'm desiring off of a high Storm count. Do note that this is purely my preference, as the Desire is a fantastic card for a dedicated Spellslinger deck. Do note that my Dralnu list is all-in on the Paradox Engine synergies and eschews the Reanimator package that your list plays with, Jenn.
Here's my Devastating Dralnu Destructor Fish-Bowl Laser Deck of Death:
1x Dralnu, Lich Lord
Mana Sources (17)
1x Everflowing Chalice
1x Mana Crypt
1x Mox Opal
1x Mox Diamond
1x Dark Ritual
1x Sol Ring
1x Mana Vault
1x Grim Monolith
1x Dimir Signet
1x Talisman of Dominance
1x Thought Vessel
1x Cabal Ritual
1x Worn Powerstone
1x Coalition Relic
1x Basalt Monolith
1x Thran Dynamo
1x Gilded Lotus
Tutors (11)
1x Mystical Tutor
1x Vampiric Tutor
1x Lim-Dul's Vault
1x Demonic Tutor
1x Transmute Artifact
1x Tainted Pact
1x Whir of Invention
1x Praetor's Grasp
1x Spellseeker
1x Intuition
1x Dark Petition
Combo Pieces/Utility (4)
1x Dramatic Reversal
1x Isochron Scepter
1x Lightning Greaves
1x Paradox Engine
1x Laboratory Maniac
1x Blue Sun's Zenith
1x Aetherflux Reservoir
Card Advantage (13)
1x Preordain
1x Ponder
1x Brainstorm
1x Mystic Remora
1x Impulse
1x Pull from Tomorrow
1x Night's Whisper
1x Necropotence
1x Windfall
1x Whispering Madness
1x Notion Thief
1x Fact or Fiction
1x Ad Nauseam
Counterspells (10)
1x Pact of Negation
1x Swan Song
1x Mental Misstep
1x Counterspell
1x Mana Drain
1x Arcane Denial
1x Trickbind
1x Muddle the Mixture
1x Disallow
1x Force of Will
Removal (10)
1x Chain of Vapor
1x Rapid Hybridization
1x Cyclonic Rift
1x Gilded Drake
1x Blink of an Eye
1x Reality Shift
1x Capsize
1x Toxic Deluge
1x Vedalken Shackles
1x Damnation
1x Polluted Delta
1x Flooded Strand
1x Misty Rainforest
1x Bloodstained Mire
1x Marsh Flats
1x Verdant Catacombs
1x Scalding Tarn
1x Boseiju, Who Shelters All
1x Academy Ruins
1x Inventors’ Fair
1x Ancient Tomb
1x Cavern of Souls
1x Urborg, Tomb of Yawgmoth
1x Minamo, School at Water’s Edge
1x Cephalid Coliseum
1x Seat of the Synod
1x Vault of Whispers
1x Command Tower
1x Forbidden Orchard
1x Underground Sea
1x Watery Grave
1x Sunken Hollow
1x Morphic Pool
1x Drowned Catacomb
1x Sunken Ruins
1x Underground River
1x Darkslick Shores
1x Snow-Covered Island
1x Snow-Covered Swamp
1x Island
1x Swamp
One Reanimation target that seems super strong is the new-ish Nezahal, Primal Tide. I'm not sure how relevant he would be in your meta but in a higher tier meta the Plesiosaur can draw an absurd amount of cards with built-in protection. Usually, there's a higher concentration of non-creature spells being cast for more competitive decks, so the Plesiosaur would get some fantastic mileage while also being a relevant attacker. Pitching cards for his Blink ability (for protection) is never a bad thing to do with Dralnu.
And besides, it's a Dinosaur. You're playing a Reanimator deck. Reanimators bring back extinct things. Dinosaurs are extinct things. You should be Reanimating dinosaurs. The end.
UB Dralnu, Lich Lord
RBW [Primer]-Kaalia of the Vast
BUG [Primer]-Tasigur, the Golden Fang
GWU [Primer]-Arcades, the Strategist
WUB Primer-Aminatou, the Fateshifter
UBR Nicol Bolas, the Ravager