As a note this is mostly just thoerycrafting right now due to the fact the meta for black Carnival hasn't been developed yet.
Black Carnival is a toolbox deck based around Valor SIGNI that wants a massive amount of cards in the trash for effects, some of her cards are based around gaining power as well.
Levels 1-3 LRIGS
As with most post incited LRIGs the choices for Carnival's lower levels is based around the number of coins you want. In key format Carnival cannot generate a coin when she grows to level two, so she currently caps out at five coins in key format. however in All-star she can have six coins. Of course you can only have five coins at a time, so if you wish to gain the maximum amount of coins use some of them for an effect or a key.
Level 4 LRIGS
Currently there is two choices for level 4's in black Carnival, Carnival †Q† and Carnival †QA†. Which of these is superior you may ask, in most cases its Carnival †Q†, while it might be more difficult to reach the condition to use her attack effect and her on-play effect may be slightly worse(as the condition on Carnival †QA† is a joke really), Joker is honestly too good to turn down in most cases. However Carnival †QA† builds will be running less keys and Carnival †QA† is the more aggressive LRIG, where as Carnival †Q† is more of a control LRIG due to where her attack being too late to open up lanes for your SIGNI so there might be merit.
Level 5 LRIG
Currently Carnival only has one level 5 and its only accessible in all-star and that card is Carnival -MAIS-, while she is a part of the red Carnival line-up, outside of ener cost she is completely generic and isn't currently being outclassed. Though running some red cards might be required to make her consistent.
- In key format, Become You, Innocent Defense, Dark Twinkle, Victim Defense, Don't Leave Me, Grave Awake and Insider Salvage.
- In All-Star Four Color Miasma, Dark Cognate, Doubt Khrysos, Cthulhu Abyss and Counter Vamp.
- Nanashi, That Hook/Myu-Velvet: I'm grouping these two together because they pretty much serve the same purpose, mill and recover+ some aggressive power. Myuu is the more potent one in most cases, however if you want to keep your exceed for something else run Nanashi. Nanashi is also more synergistic with one of Carnival's cards and may turn out to be superior, especially when Carnival gets more support.
- Mel-Muddler: Some of Carnivals cards want to be boosted power wise to activate some pretty good effects, Carnival seems like she wants quite a bit of ener. However there might not be enough targets for her currently, and her self trashing effect doesn't seem like its that useful for Carnival
- Tawil, Who Reaches Out: Stopping yourself from refreshing can be nice, also decent removal and can be used as a tutor.
Level 1 SIGNI
The most relevant level 1 black Valor cards are:
- Guinevere, Queen of the Round Table: Delayed ener generation, usually will generate one to two extra ener.
- Semiramis, Black Mage of Doves: Trash Set-up, milling three is a good effect.
- Zhang Liao, Two-Handed Axe of the Wei Army: Combo piece, lets you power-up one of your other Valor SIGNI to some pretty impressive numbers.
- Morgan, Apparition of the Round Table: Removal, requires a lot of work to be useful.
- Kibitsuhiko, Peach General of Bitchu:(All-Star Only) a plus engine that sacrifices some aggressiveness on average. Source of red ener.
- Douzan, Oil Viper of Mino:(All-Star Only) a less passive plusing engine, mildly reliant on the opponent. Source of red ener.
- Yellow Turban, Yellow Soldier of Uprising: (All-Star Only) consistency booster, while also a source of red ener its not usually a very good one.
Level 2 SIGNI
The most relevant level 2 black Valor cards are:
- Vlad, Prince of Impalement: Trash set-up and combo piece, while worse as a combo piece than Zhang Liao, she mills and outside of one card right now the massive gains of Zhang Liao are not needed, though she can whiff even on small boosts.
- Charlotte, Ruthless Daughter: Ener generation, she is only useful from the trash, so running only a few copies is optimal if ran at all.
- Danzo, Kite Ninja of Genjutsu: Removal, she's strong early game removal and unlike Morgan doesn't need as much work to be optimal.
- Elina, Pursuer That Severs Shadows:(All-Star Only)Easy removal and easy double crush. Source of red ener.
Level 3 SIGNI
The most relevant level 3 Black Valor cards are:
- Kirizo, Concealment of the Ten Braves: Combo piece, can pump-up cards; she seems bad but might be useful.
- Xiahou Yuan, Red Bow of the Wei Army: Pulls a level 3 or lower SIGNI from the trash, one of the few cards that Carnival has right now that plays from the trash.
- Elizabeth, the Blood Countess: Removal that only works when played from the trash, works well with Xiahou Yuan.
- Akemitsu, Honnō-ji Rebellion: Strong removal that relies on having her power boosted.
- Tokisada, Shimabara Rebellion: Decent removal that also mills.
- Liliana, Pirate of Aesthetics:(All-Star Only) Removal and plays from the trash, she synergies with the power boosters as well. Red ener source.
- Galahad, Bloody Spear of the Round Table:(All-Star Only) Removal, outclassed by Liliana. Red ener source.
- Zhurong, Flaming Body of the Four Prefectures:(All-Star Only) Consistency booster, red ener source but suffers the same problem as Yellow Turban.
Level 4 SIGNI
The most relevant level 4 Black Valor cards are:
- Lancelot, Immorality of the Round Table: Plays a black SIGNI from the trash, sacrifices some aggressiveness on average. this might be for the best to synergies with Carnival †Q†.
- Merlin, Prophecy of the Round Table: Recurs itself from the trash and can nuke fields, not that good in multiples and can clog the field.
- Sima Yi, Strategist of the Wei Army: Strong removal, sort of part of the power boost, but rarely needs to be boosted.
- Xiahou Dun, One Eye of the Wei Army: Good cheap removal.
- Mordred, Rebellion of the Round Table: Great removal that relies heavily on power boosts.
The most relevant spells for black Carnival
- Melt Death Size: Strong cheap removal that mills.
- Recycle Deads: Mills and plays a Valor from the trash, synergies well with Merlin.
In her current state, Black Carnival doesn't have much choice in variety, though this is to be expected from a deck with one wave of support. Heres an attempt at a key format deck, I'll probably improve it when I figure out the deck more.
- Carnival †PA†
- Carnival †S†
- Carnival †TA†
- Carnival †Q†
- Tawil, Who Reaches Out
- Nanashi, That Hook
- Victim Defense
- Innocent Defense
- Fate Struggle
- Recycle Deads x 4
- Guinevere, Queen of the Round Table x 4
- Semiramis, Black Mage of Doves x 4
- Vlad, Prince of Impalement x 1
- Danzo, Kite Ninja of Genjutsu x 3
- Xiahou Yuan, Red Bow of the Wei Army x 3
- Elizabeth, the Blood Countess x 1
- Tokisada, Shimabara Rebellion x 3
- Lancelot, Immorality of the Round Table x 1
- Merlin, Prophecy of the Round Table x 2
- Sima Yi, Strategist of the Wei Army x 2
- Xiahou Dun, One Eye of the Wei Army x 4
- Servant O2 x 4
- Servant D2 x 4