Should You Pull? (TLDR):
The most maybe of all time.
Are you looking to build the Conduit/Instrument Archetype?
Gameplay and Review
Gameplay
The Twins have a very straightforward gameplan, and actually zero unique effects making them relatively easy to explain.
Their Insights provide them with a textwall worth of effects, due to their nature as a collab character they get a bunch of extra gimmicks from this to help them stand out from the rest of the cast.
They can switch between Mineral and Star Afflatus based on whether they have Set A (Mineral) or Set B (Star) equipped during combat.
Due to technically being two characters in one, they add a permanent +1 to your AP which can stack with [Continuous Action I].
Additionally, your hand size is increased by +2 due to this.
The Twins are able to equip two unique Psychubes at the same time.
They have an increased Energy Deck, having to supply both Mineral and Star Energy.
Enemies dealing Afflatus Advantage DMG to them deal -30% DMG.
And these are just the benefits they get from existing as a collab character. The rest of their Insights are focused around generating Energy, such as allowing you to draw a selected Energy card or drawing set Energy cards when breaking Afflatus Resistance. There are bits of Harmonization generation here and there to smooth out their rotation.
Their actual Basic Incantations are split into two sets: Set A and Set B.
Set A is the Mineral set. “Atomic Fusion” grants a big +4 Mineral Energy, which is important as the attacking Incantation of this set costs at least 3 Mineral Energy. “Polymeric Ray” is a Mass Attack whose damage scales with the amount of Mineral Energy used this turn. This makes stacking Mineral Energy really important, and makes Coppelia an important supportive piece for any team involving the Twins.
Set B is the Star set. “Extreme Overclocking” grants a raw Crit Rate/DMG buff to the Twins for this turn but can only be used once due to its [Interval] on trigger. “Balancé Across the Stars” is a low-cost Mass Attack that increases in damage every time it is used this turn, making it imperative that you stack up on at least 4 Star Energy to max out these benefits.
“Technological Breakthrough” is a big Mass Attack with ridiculously high scaling that deals both Mineral and Star Afflatus DMG. It consumes all Energy on use, and gains massively increased Reality DMG and Crit Rate / Penetration Rate / Crit Conversion when 6/9/12 Energy is consumed.
Review
The Twins are in a really tough spot to review.
Objectively, they’re incredibly strong. They don’t have a high ‘bullshit’ factor (having literally no new effects or unique buffs) and simply just have bigger multipliers than the rest of the cast. In a Conduit team that can hit their Energy breakpoints (especially those of “Polymeric Ray” and “Technological Breakthrough"), the Twins are in the Top 5 Damage Dealers in mid-length fights.
They have lots of Mass DMG, and their ridiculous multipliers allow them to bypass the need for
That also spells out their biggest problem: Conduit.
The CN server does not face this issue, as the collaboration was released for them after Anniversary and 3.8 and thus they have access to Coppelia, Rhiannon and most importantly Everecho. However, Global does not have this luxury.
The Twins are quite literally barely playable if not outright dysfunctional on Global. Their Energy needs are very intensive, requiring Coppelia and Everecho to hit the breakpoints on quite literally every single one of their attack Incantations/Ultimate. Unfortunately, none of those characters are released on Global as of writing this. You’re forced to use them without any Energy companions which results in your hand getting clogged with standard cards. Since Energy cards are special cards, you can’t use Tuning to shuffle your hand into Energy cards or force Energy cards to appear. If you’re very lucky, you’ll get maybe up to 3-4 of either Mineral or Star Energy per round, which feels genuinely abysmal when it comes to trying to play the Twins.
It is so diabolical, in fact, that the Twins cannot hit 10M points on the Mane’s Bulletin boss specifically designed for them and their archetype (assuming P0).
The worst part? It’s going to take another two weeks for Coppelia and Rhiannon to release, and then another month and a half (so effectively two months total) for Global to get Everecho. By that time, a new and shiny archetype could be released on CN, making the Twins difficult to recommend at all despite their power in a full Conduit team.
Extremely high damage output.
Collab gimmicks give them a bit of unique utility that no other characters have.
Little to no personal buffing or support.
Extremely tied to Conduit due to Energy needs to hit Incantation breakpoints.
Barely playable / extremely dysfunctional due to release lineups.
Portrait, Synergies, Psychubes and Resonance
Portrait
The Twins are complete at Portrait 0.
Vertical investment is not recommended, as it only improves what is already there (their rare damage numbers). However, due to being a collab character, it is fairly easy to get their Portraits if desired.
Great Synergies:
The Twins are a Conduit Damage Dealer, and tied to the hip to their archetype.
Conduit:
CoppéliaOther:
Cheng Heguang, 
Charon, 
Flutterpage
Psychubes:
The Twins have two unique Psychubes that they can equip at the same time.
The Art of Atoms (Twins Sig): Boosts Crit DMG quite significantly if “The Dance of Science” is also equipped and adds a bit of Conduit DMG Bonus.
The Dance of Science (Twins Sig): Boosts Crit Rate greatly if “The Art of Atoms” is also equipped and adds another big DMG Bonus on top.
Resonances:
Code - APQkOAUoRDxjOUItQCZQJQQ0IjQgKAEqAA
Recommended Pattern is Elucidation
Team:
Euphorias: N/A
Conduit is an archetype that looks very complicated, but really just inserts a layer between your casting Incantations and them triggering from the AP Area. The benefit is that so long as you gather enough Energy, you can unleash way more Incantations than normal (non FUA based) teams. The hand becomes largely irrelevant, and you’re only tied down by getting the right Energy to trigger the right casts, which removes a lot of the RNG involved with rotations.
That does assume you’re in a team of mostly Conduit characters. Having only one Conduit unit in the team (like Global currently) makes it really difficult to play due to other characters clogging the hand with normal cards, preventing Energy cards from being drawn.
In this team, you’re just about doing everything that the Twins realistically want.
Coppelia provides additional Mineral Energy, and she also benefits from allies utilizing Mineral Energy which the Twins do quite often. Since Set B Incantations are cheaper to cast, you don’t necessarily need a dedicated Star Energy character like Regulus(E2). Instead, Rhiannon is used because she can cast all her Incantations for free permanently after her first Ultimate, clearing the hand to draw more Energy.
Everecho is the driving force of the Conduit archetype. Besides her powerful healing and defensive options, her strong debuffs and especially her Chaotic Energy generation allow the Twins to stock up on large amounts of energy for their expensive Set A casts and the breakpoints on their Ultimate.
Conduit excels in mid-length fights primarily because of Everecho. Healing still isn’t good in longform content like Mane’s Bulletin even when considering that Everecho has access to ‘reverse Shield’ with her [Remembrance] effect meaning that the team is a lot squishier than a lot of other teams. The lack of ‘bullshit’ effects (beyond Rhiannon) in this team also makes them lose out on damage that other teams are dealing when taken into long stretches of combat.