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Moon Cancer
April Fool's
Chaotic Good
Max HP 13,643
HP Rank
Max ATK 8,197
ATK Rank
Base Atk1,366Base HP2,182
Max Atk 8,197 Max HP 13,643
Grail Atk 9,925 Grail HP 16,542
NP per Hit (%) 0.61%
NP when Attacked (%) 3%
Star Absorption 52
Star Generation per Hit 14.7%

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Servant Skills

Domina Cornam D

Removes one ally's debuffs.
Recovers their HP.
Grants them Debuff Immunity for 1 time, 3 turns.

Show Info
Heal + 1000120014001600180020002200240026003000
CD 6 6 6 6 6 5 5 5 5 4

Available from the start

Aurea Poculum C

Removes one enemy's Evasion and Invincibility buffs.
Chance to Stun them for 1 turn.

Show Info
Stun Chance + 50%55%60%65%70%75%80%85%90%100%
CD 8 8 8 8 8 7 7 7 7 6

Unlocks after 1st Ascension

Self-Modification EX

Increases own critical damage for 3 turns.
Increases own critical star absorption for 3 turns.

Show Info
Crit Damage + 20%23%26%29%32%35%38%41%44%50%
Absorption + 400%440%480%520%560%600%640%680%720%800%
CD 7 7 7 7 7 6 6 6 6 5

Unlocks after 3rd Ascension

Class Skills

Magic Resistance B

Increase your Debuff Resist by 17.5%.

Item Construction A

Increase your Debuff Chance Rate by 10%.

Territory Creation A

Increase your Arts Card effectiveness by 10%.

Noble Phantasm

C.C.C. A

Deals damage to a single enemy.
Increase NP Gauge for all allies by 20%.


Decrease Debuff Resist for a single enemy (3 turns).

Show Info


Cursed Cupid Cleanser

Rank Classification Hit-Count
A Anti-Unit 5

Deals damage to a single enemy.
Increase NP Gauge for all allies by 20%.

Level 1 2 3 4 5
900% 1200% 1350% 1425% 1500%
20% 20% 20% 20% 20%
Overcharge Effect

Decrease Debuff Resist for a single enemy (3 turns).

Charge 100% 200% 300% 400% 500%
10% 20% 30% 40% 50%

Assorted Info

ID 166
Cost 12
Gender Female
Growth Linear
Inst. Death Chance 0.60%
Damage Distribution Quick 10,20,30,40
Damage Distribution Arts 16,33,51
Damage Distribution Buster 100
Damage Distribution Extra 10,20,30,40
Damage Distribution NP 6,13,20,26,35

Attack / HP Growth

Stat Ratings

Ascension Materials


Skill Enhancement Materials

1 → 2 100,000
2 → 3 200,000
3 → 4 600,000
4 → 5 800,000
5 → 6 2,000,000
6 → 7 2,500,000
7 → 8 5,000,000
8 → 9 6,000,000
9 → 10 10,000,000

Costume Dress Materials

Costume Cost Materials
April Fool's

Bond CE

Bond Level 1 2 3 4 5 6 7 8 9 10
Bond Pts Req. 3,000 6,125 6,125 6,125 6,125 262,500 290,000 300,500 309,500 315,000
A Passerby's Dream

When equipped on BB,
Increase all allies' Buster, Quick, and Arts Card effectiveness by 8% while she is on the field.

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I'm a final boss-type kouhai who can do anything!

This ever-reliable, entirely benevolent, and certainly-not-scheming kouhai from the Moon Cell cheats her way into Chaldea as the first Moon Cancer Servant in the game. With just a little pinprick, BB is an Arts Servant that moonlights as a centerpiece for Arts teams, either as a support, a damage-dealer, or simply a mixture of the two.

With excellent generation stats, even capable of creating a tidy sum of critical stars, BB is a Servant with all-around great performance. Despite her low base attack stat, her welfare status and Territory Creation ensure that her Arts NP hurts regardless. In addition, BB packs the same rank of Self-Modification skill as Jeanne d’Arc (Alter): an awesome combination of Star Gathering and Critical Damage buffs. Her NP itself refunds well too, with 5 hits and most importantly, a static 20% NP charge to every member of the team - BB herself included. Lastly, next to her NP charging and healing support, BB packs amazing utility, with access to a Stun, Evasion/Invincibility Removal, Debuff Cleanse, Debuff Immunity and a Debuff Resist Down on Overcharge.

Still, as is common with most Extra class Servants, BB in most cases will hardly be able to leverage any sort of class advantage against her enemies. Due to that, her low base attack, and lack of high class-based damage modifiers to compensate, BB ends up as a very consistent, but still rather slow damage-dealer. In addition, while she packs some great support, they are mainly effects ideal for challenging content while her overall skill set is rather selfish in practice. Her support works best when BB is the focus of attention, which this devilish kouhai no doubt intended.

Taken in her entirety, BB is an example of an Arts hybrid done right. Her performance as a main Arts damage-dealer supported by others is stellar, while her support potential shines in challenging content or for fights where debuff cleansing is essential. No matter the situation, our kouhai is able to show us how it’s done.

Gameplay Tip 1

Moon Cancers complete the Ruler-Avenger triangle, by dealing class advantaged damage to Avengers (and Berserkers) while Rulers (and Berserkers) deal class advantaged damage to Moon Cancers.

With Caster-level Star Weight, base star generation only second to Assassins, and 1.0x damage modifiers, the Moon Cancer class lacks any strong inherent weaknesses that plague some of the Caster and Assassin Servants.

Gameplay Tip 2

A generally unimportant and overlooked statistic on any Servant page is the Instant Death Chance parameter: the chance that each Servant is affected by an enemy Instant Death effect.

Unlike strong enemies, Master-owned Servants are a lot more vulnerable to the mechanics of Instant Death. Some Challenge Quests do have enemies with punishing Instant Death Noble Phantasms, or even basic attacks.

If any enemy encounters rely heavily on Instant Death Chance, remember our favourite devilish kouhai, as her Instant Death Chance statistic is spectacularly low at a measly 0.60%, perhaps as a lore nod to her AI nature.


Versatile Arts Lynchpin

The nature of BB’s class and kit allows her to work effortlessly in any variety of Arts teams and against any (non-Ruler) opponent. With constant Arts chains and the NP charging from her NP, Masters will not only see BB NP often, but her team as well. Next to NP spamming Arts teams, her reliable stun from Aurea Poculum and constant NP charging make her fit well into Arts stalling teams too. Lastly, her Self-Modification and good star generation allows her to fit seamlessly  into any Arts Critical team as well.

Healing, Cleansing and Removal Support

BB’s Domina Cornam functions as a low cooldown heal with both a debuff cleansing effect as well as a single-use debuff immunity. This makes BB an ideal companion during quests with debilitating debuffs, but also an ideal companion to any Servants with powerful demerits in their kit. The debuff immunity effect itself can be used ahead of time to prevent BB or the targeted Servant from being disabled by enemy skills or NPs. Furthermore, her Evasion and Invincibility removal from Aurea Poculum is no slouch either. Sheer removal is generally preferable to any self-buffs that can Pierce these protections as the entire team can then continue to hit the enemy.

NP Spam potential

In ideal situations, BB can refund her NP even with minimal additional support. With the strong Star Gathering buff from Self-Modification, her static 20% NP charge (it does not scale with overcharge!) and her Territory Creation, any NPAA-chain with easy to access Arts criticals can result in BB performing back-to-back NPs.

Avenger Class Advantage

Lastly, the Moon Cancer class is the only class with full class advantage against Avenger Servants. While Avenger enemies are rare, they are typically some of the most aggressive and dangerous opponents. Masters who prefer a steady and safe approach against Avengers will find great comfort in BB’s Moon Cancer class.


Few Opportunities for Class Advantage

With few opportunities to truly exert her class advantage, BB’s damage for general farming (or even for setups where speed is paramount) is notably less impactful. Given her low base attack and lack of strong non-critical steroids, Masters may prefer class-advantaged Servants and more direct counters instead once their roster is large enough. However, BB is always a good secondary option for almost any encounter.

Lack of Burst Damage

In her damage-dealer role, BB is built to meticulously explode enemies into a fine paste over time, while her NP charging support is locked behind her ST NP. Thus, BB is ill-suited for farming compositions outside of her cleansing support.

Selfish Support

In practice, despite her plethora of support effects, BB plays mainly like a selfish support who functions at her best when she is graced with plenty of active Command Card use. With her Self-Modification skill being purely selfish and even capable of taking precious critical stars away from allies for 3 turns, all the while her NP charging is only accessible on NP usage, BB is hamstrung if she can’t get the attention she deserves.

Lack of Hard Survival

Given her stalling, high base HP and healing support, BB is sturdier than many of her peers that also lack a hard survival skill even if she commonly receives class neutral damage. Nonetheless, during challenging encounters, BB will prefer a team that can deal with an enemy NP for her, either through stalling or via protection skills.

Level Up Skill Recommendation

As a unique welfare Servant with excellent scaling on all her skills, any Master is heavily recommended to eventually go all the way on all of her skills. The order in which to do so can vary, however. Masters who prefer her support potential can invest first in her Domina Cornam, while Masters who wish to deal more damage and destroy Avengers will find more powerful critical potential in her Self-Modification. Even her Aurea Poculum could be leveled first for Masters who prefer stalling-oriented compositions where cooldown reduction is essential - or where the small chance for a resist can prove disastrous. For general use though, we recommend the following:

  • Her main healing and cleansing skill, Domina Cornam D, scales very well with additional ranks. While the added healing is nice, the cooldown reduction is the real treat, as a 4-turn base cooldown allows BB to spam Domina Cornam frequently and with little consequence. For her support it can generally be leveled first simultaneously with Aurea Poculum.

  • Aurea Poculum C is mainly BB’s non-conditional stun skill. Stuns are some of the most powerful debuffs and with BB’s Item Creation & Debuff Resist Down on Overcharge, it will land reliably even at lower ranks. Its secondary effect is no slouch either as it strips any enemy of their Evasion and Invincibility buffs - great for Challenge Quests where enemies cannot be one-shot and they will cast their survival skills. For her support, level this simultaneously with Domina Cornam.

  • BB’s primary damage skill, Self-Modification EX, is one of the strongest critical skills in the game. Its 3-turn duration, powerful scaling, and short cooldown when maxed all nudge Masters towards leveling it first. For Masters who wish to use BB for her all-purpose damage potential or Avenger destruction, this skill should be leveled first. Otherwise level it last as it may well be left unused in her support role.

Craft Essence Recommendation

As befits her role as a hybrid Servant, BB can field a staggering numbers of CEs and perform well, with Arts Performance Up CEs always being a safe bet. In her role as a damage-dealer BB can either focus more on her Arts critical potential through Critical Damage Up, or on her Arts NP spam with NP Damage Up or NP Generation Up. If in her role as support, both Passive Critical Stars, Healing Effectiveness Up, and Passive NP Gauge are excellent picks.

  • Formal Craft / Kaleid Sapphire / Projection: The general all-purpose Arts options work well with her base kit and work very well for her refund potential if she lacks Arts performance buffs.

  • Black Grail / Cute Orangette: Given her own low cooldown healing capabilities, the Black Grail is an impressive and powerful CE option that is ideal for compositions where she has access to additional NP charging supports. Cute Orangette stacks multiplicatively with Arts Supports and her own Territory Creation, which is great for successive NP spammage.

  • Another Ending / Chocolatier / Hot Spring Under The Moon: Another Ending is a superb option for improving BB’s critical potential, but it does stack additively with her own buffs and passive. Granting her a few passive critical stars is quite potent as her own star generation is often not quite enough.

  • A Fragment of 2030 / Prisma Cosmos / Gentle Affection: With BB taking on a support role, her own low base Caster-like Star Weight makes her an ideal holder for A Fragment of 2030. But if either her NP charging support (through more frequent NPs) or her healing support needs a boost, the alternatives are solid options.

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Other Info

Release Date
AKA/Alias/Nicknames Mysterious Black Magus
Country/Place of Origin
Illustrator Wada Arco
Seiyuu (CV) Shitaya Noriko
Series Fate/EXTRA CCC




Welfare - A free Servant acquired from completing an Event.

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