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Last updated: 22/May/2026
Best guide and build for Rei from Chaos Zero Nightmare (CZN). Rei is a 4✦ character from the Controller class and Void attribute, who belongs to the Terrascion [SS Edenity] faction.
Last review update
Season 2
Last build update
Season 2
Last profile update*
15/Mar/2026
*Profile update means updates done to reviews/builds/gear within a season - showing the last date we changed anything on this page.
To learn more about Rei check the sections below. Use the tabs to quickly switch to the kind of information you're looking for.
Profile
Dark Blade
Attack
Material Regeneration
Skill
Show Effects
Strike of Darkness
Attack
Show Effects
Resonating Darkness
Upgrade
Show Effects
Snack Time
Skill
Show Effects
Dark Condensation
Skill
Predator's Blade
Attack
Show Effects
Final Shadow
Ego Skill
Epiphany cards are special evolutions for the cards you can obtain while playing the roguelike mode. Only some cards in the character's deck can get Epiphany effects. Since there's quite a lot of them, we don't display them by default - press the button below to show them.
Epiphany Bonus
Potential 1
Basic Card Upgrade
Potential 2
Common Card Upgrade
Potential 3
Basic Card Proficiency
Potential 3-1
Unique Card Upgrade
Potential 4
Health Proficiency
Potential 5
Basic Card Proficiency
Potential 5-1
Divine Epiphany Adaptation
Potential 5-2
Attack Proficiency
Potential 6
Unique Stat Upgrade
Potential 7
Sleeping Memory
Manifest Ego 1
Awakening Memory
Manifest Ego 2
Vivid Memory
Manifest Ego 3
Inner Memory
Manifest Ego 4
Complete Memory
Manifest Ego 5
Liberated Memory
Manifest Ego 6
Review
Rei is a Void attribute Controller who specializes in buffing her allies whilst offering adequate healing through Chaos. Still, ultimately, it isn't Rei's main goal and isn't something she can excel at compared to other Controllers.
Rei is proficient at providing huge buffs to her allies' damage output via either Morale or direct card buffs from her Resonating Darkness and Dark Condensation cards, whilst also putting out some damage of her own, thanks to her Strike of Darkness and Predator's Blade’s cards, which also provide temporary one-turn buffs. Rei also offers some light healing, Card Draw and offers a source of [Exhaust] from her Snack Time card.
Rei has some extremely flexible Epiphanies on her cards that can adjust the requirements for her buffs to take place that can allow her to shine even further. Due to the nature of her additive bonuses, she is best paired with DPS characters who have lower base values or multihitters.
Rei, however, does lack a solid source of healing as her Basic Cards are often removed, but with some Potentials and her Ego2 unlocked, can provide some okay healing when using her Attack Cards.
If you have a DPS who benefits greatly from small additive damage multipliers or characters who multi-hit, Rei could definitely be one of the best choices to really amp their damage.
Incredibly potent and numerous buffing cards and upgrades.
Can deal some decent damage herself for a support with Epiphanies that support this.
Has [Exhaust]-based Card Draw and deck thinning, which can be enhanced further via Epiphanies.
Deals significant Tenacity Damage via Ego Skill.
Most buffs are incredibly specific and conditional.
Many buffs last only one turn or work for one specific card.
The ratings below are based on the Season Save Data, Chaos Manifestation, and Great Rift modes. Each of the modes values different mechanics, so some characters may shine in one of them, while being underwhelming in the other.
Multiplicative +% DMG: Rei’s kit features both Additive +% and Multiplicative +% DMG buffs and understanding the difference between them is important. Multiplicative +% Increased DMG improves only the base card damage multiplier by the listed amount (e.g., 100% increased by 120% is 240%).
Additive +% DMG: Additive +% doesn’t interact with the base damage multiplier of cards and instead adds its listed amount on top of whatever the cards' listed damage shows (e.g, 100% +40% is 140%).
Rei’s Signature Potentials mostly enhance her personal damage and not much utility, meaning if you don’t care for that, they are optional.
3-1: Grants her Dark Blade Attack Card a 20% Damage based Recovery, providing some solid healing that is mostly useful for Chaos.
5-1: Increases Dark Blade’s damage multiplier by +5% with an additional +5% granted if ATK exceeds 500.
7: Significantly increases Predator's Blade’s damage by +10% while Rei’s ATK is higher than 550. Also grants an additional +1% multiplier per 10 ATK over 550 up to 20%.
Base
Ego 1
Ego 2
Ego 3
Ego 4
Ego 5
Ego 6
Final Shadow
Ego Skill
Costs 4 EP to use and delivers a solid amount of damage while also recovering 1 AP. The AP is an excellent burst of momentum and the damage can knock out problematic enemies as well. It should be used when you need extra resources.
Dark Blade
Attack
Rei’s Basic Attack gains some nice damage bonuses from her Potentials and if needed, serves as a “Basic Attack” for the purpose of her own buffs. Ideally, you would aim to align them with your DPS, though. It also provides ample healing as it will heal for 20% of the damage dealt when her 3-1 Potential has been unlocked.
Material Regeneration
Skill
Show Effects
Rei’s basic heal. Gains no additional functionality and isn’t an important card for her overall strategy unless you specifically need to boost team healing slightly.
Strike of Darkness
Attack
Show Effects
Deals some up-front damage, then buffs all Basic Attack DMG by a Multiplicative +100% for 1 turn. This is a potent buff for Basic Heavy DPS, but it isn’t as useful for Combatants that aren’t. This card also has [Lead], allowing it to sometimes be used for free. Should be used before any other cards to capitalize on [Lead].
Resonating Darkness
Upgrade
Show Effects
Another buff, this time an upgrade that persists the whole fight after use. Grants all 1 cost cards an additive +40% DMG, which is generic enough that most DPS can mostly take full advantage. It should be established as soon as possible for maximum value.
Snack Time
Skill
Show Effects
A heal, draw and targeted [Exhaust] from hand all in one for the low cost of 0AP. To use, a card from the hand must be selected to exhaust for the rest of the combat. This might sound like a downside, but it can simply be treated as a pseudo Card Removal, making it pure upside unless every card in your deck/hand is good. While strong, it also has [Exhaust] itself, meaning it can only be used once.
Dark Condensation
Skill
On use allows 1 Attack Card to be selected and its damage is increased by an additive +100% until next used. A strong and flexible effect, but quite expensive compared to other similar buff effects, which either last multiple turns or affect multiple cards.
Predator's Blade
Attack
Show Effects
Deals some damage, then grants 2 Morale (additive +40% DMG) for 1 turn. Rei’s most generic and unrestrictive buff, making it one of her better ones baseline, even if the damage boost it offers isn’t the highest for its 1 turn duration.
Best Epiphanies
Note
We have given a star rating for each Epiphany, showing how strong and useful it is - with 1 being the lowest rating and 5 the highest.
Strike of Darkness I
Attack
Show Effects
Strike of Darkness II
Attack
Strike of Darkness III
Attack
Show Effects
Strike of Darkness IV
Upgrade
Show Effects
Strike of Darkness V
Skill
Show Effects
Epiphanies:
Divine Epiphanies:
Which Divine Epiphany to go for will depend on what your team needs and which Epiphany you chose, but here are the main ones to look out for if you have spare Save Data: Morale/Resolve (Strike of Darkness IV), -1 Cost Reduction.
Resonating Darkness I
Upgrade
Show Effects
Resonating Darkness II
Upgrade
Show Effects
Resonating Darkness III
Upgrade
Show Effects
Resonating Darkness IV
Upgrade
Show Effects
Resonating Darkness V
Skill
Show Effects
Epiphanies:
Divine Epiphanies:
Which Divine Epiphany to go for will depend on what your team needs and which Epiphany you chose, but here are the main ones to look out for if you have spare Save Data: Morale/Resolve, Draw 1 (Resonating Darkness V).
Snack Time I
Skill
Show Effects
Snack Time II
Skill
Show Effects
Snack Time III
Skill
Show Effects
Snack Time IV
Skill
Show Effects
Snack Time V
Skill
Show Effects
Epiphanies:
Divine Epiphanies:
Which Divine Epiphany to go for will depend on what your team needs and which Epiphany you chose, but here are the main ones to look out for if you have spare Save Data: +1 AP.
Dark Condensation I
Skill
Dark Condensation II
Skill
Dark Condensation III
Skill
Dark Condensation IV
Skill
Dark Condensation V
Upgrade
Epiphanies:
Divine Epiphanies:
Which Divine Epiphany to go for will depend on what your team needs and which Epiphany you chose, but here are the main ones to look out for if you have spare Save Data: Draw 1, -1 Cost Reduction.
Gear
The Memory Fragments & Equipment suggestions below are based on calculations we did. If you want to check the damage formula and how scaling the damage works in CZN, check this guide.
Rei is easily able to max out Glory Reign's effect to grant the entire team a 15% (multiplicative) damage boost permanantly so long as she's running multiple Snack Times which most of her most common builds do. It's important to Note that Glory Reign's effect cannot be stacked so you only want to run 1 set of it per team.
Use either 2P Tetra's for a tankiness and a healing boost or 2P Healer's Journey to bolster the overall HP total of the team.
Only recommended if you already have a 4P Glory's Reign user on your team otherwise you should just use that set instead. If running 2/2/2 though it's best to run 2P Healer's Journey with 2P Tetra's to maximize surviability and healing.
Use either Seth's Scarab to boost the healing and damage output of Basics for early chaos comfort or 2P Blackwing to boost Rei's overall damage output which will also still offers some healing early in chaos runs thanks to the damage to healing conversion from Dark Blade. Alternatively you can also bypass these small bonuses in favor of using non-set pieces to target better main/sub stats.
In a lot of cases, flat sub-stats are better than percentage ones when it comes to HP, ATK and DEF. The reason behind this is that in CZN the characters stats are pretty low and you get more value from flat bonus rather than percentage one based on calcs.
DEF > DEF% > EGO Regen = HP > HP%
Our best Partner recommendation try to balance both the raw damage boost they provide based on our calculations with the additional utility provided by the skill - combined with how it interacts with the character's kit. We have rated each Partner based on how much additional damage and the utility they provide. Read the comments under each Partner to better understand our reasoning.
No calculations in Chaos Zero Nightmare are completely accurate for all scenarios, including the ones below. What team, decks, epiphanies, gear, equipment, and enemies you're facing all impact them. Because of this, take the results as guidelines and combine them with the explanations to make your decisions. Calculations use endgame save data set-ups, including 5 turns of combat using the whole deck with all Ego skills unless otherwise stated.
Nyx is a safe all-around choice for Rei thanks to her ability to churn through 4 cards of the deck with her Ego Skill while also still having some multipliers to survivability and healing. Nyx also does offer a small buff, which is nice, but it's worth noting that after Snack Time is exhausted, Rei doesn't naturally have any other ways to draw in her base card pool, making keeping this buff up dependent on your deck. The one downside of Nyx is that her Ego Skill costs 4EP, which in Save Data game modes usually means you won't be able to easily use it in Turn 1, something the other main supportive Draw Partner Yuri, is capable of. All up, if you need Draw Power or value the Passive stats Nyx provides, she's a safe pick for most teams, but if all you care about is survivability/combo potential, check out other options as they may suit your needs better.
Yuri isn't a Controller Partner, so her Passives don't work. However, that doesn't disable her Ego Skill, which is a potent Draw 2 for 2 EP. Yuri is an alternative option to Nyx, which can be used in Turn 1 in Save Data and is far more accessible and spammable in Chaos. If that appeals to you and you're ok downgrading how many cards you're drawing and losing out on all the Passives Nyx provides, you can use Yuri instead.
Arwen is one of the top options when it comes to survivability, thanks to her great Passive Stats, which boost both healing and total team health, but most of all her constantly refreshing Damage Reduction. If you're struggling to stay alive and need more survivability, especially in fights that launch large but infrequent attacks, giving up utility or draw for Arwen can be worth considering, especially in Chaos-based game modes.
Alyssa works as an alternative to Arwen with quite a different stat line, favoring Combat Defense and Passive Healing instead. Usually not as universally strong for survivability as Arwen, but if you value the higher defense over Arwen's higher HP total and mitigation buff, she can be a more appealing option.
A F2P survivability option that falls behind both Arwen and Alyssa in most cases, but is still an acceptable choice if you have neither of them available at an acceptable Ego level.
In the Zero System, it's incredibly easy to access all items acquirable via the shop thanks to the five free refreshes you get each shop node - that's why the recommendations below are limited to them only. ATTENTION! Area-specific items can sometimes be more powerful than shop items, but are far less consistent to get or require running a specific world or giving up certain event options. Use the shop list as a starting point for building up your deck saves.
The equipment recommendations are based on items obtainable in Season 2’s Chaos - Burning Life. If you’re running content outside of Season 2, it’s possible some options may not be available for acquisition, or that other options not obtainable in Burning Life may be better.
We're currently working on updating all builds for Season 3.
Deck & Teams
Check the best builds for Rei below.
OTK Draw
Basic Attack Buffer
Season 2 Ebony Lumen Draw
Exhaust Support
Generic Morale Buffer
Strike of Darkness IV
Upgrade
Show Effects
Snack Time II
Skill
Show Effects
Predator's Blade
Attack
Show Effects
Base performance of the character.