Cu Chulainn (Alter)

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April Fool's
Chaotic Evil
Max HP 12,210
HP Rank
Max ATK 12,805
ATK Rank
Base Atk1,979Base HP1,790
Max Atk 12,805 Max HP 12,210
Grail Atk 14,017 Grail HP 13,377
NP per Hit (%) 0.69%
NP when Attacked (%) 5%
Star Absorption 9
Star Generation per Hit 5.1%

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Servant Skills

Madness of the Spirits A

Reduces all enemies' attack for 3 turns.
Reduces their critical attack chance for 3 turns.

Show Info
Attack - 10% 11% 12% 13% 14% 15% 16% 17% 18% 20%
Crit Chance - 30% 32% 34% 36% 38% 40% 42% 44% 46% 50%
CD 8 8 8 8 8 7 7 7 7 6

Available from the start

Protection from Arrows C

Grants self Evasion for 2 attacks.
Increases own defense for 3 turns.

Show Info
Defense + 7% 7.7% 8.4% 9.1% 9.8% 10.5% 11.2% 11.9% 12.6% 14%
CD 7 7 7 7 7 6 6 6 6 5

Unlocks after 1st Ascension

Battle Continuation A

Grants self Guts status for 1 time, 5 turns.

Show Info
Revives with 1000 HP1150 HP1300 HP1450 HP1600 HP1750 HP1900 HP2050 HP2200 HP2500 HP
CD 9 9 9 9 9 8 8 8 8 7

Unlocks after 3rd Ascension

Class Skills

Madness Enhancement EX (C)

Increase your Buster Card effectiveness by 6%.

Divinity C

Apply Damage Plus for yourself (Total Card Damage +150).

Noble Phantasm

Curruid Coinchenn A

Deal significant damage to a single enemy


Increase your ATK (1 turn).
Increase your DEF (1 turn).

Show Info

Curruid Coinchenn

Beast of Crunching Death Fangs

Rank Classification Hit-Count
A Anti-Personnel 12

Deal significant damage to a single enemy

Level 1 2 3 4 5
600% 800% 900% 950% 1000%
Overcharge Effect

Increase your ATK (1 turn).
Increase your DEF (1 turn).

Charge 100% 200% 300% 400% 500%
30% 40% 50% 60% 70%
30% 40% 50% 60% 70%

Assorted Info

ID 98
Cost 16
Gender Male
Growth Reverse S
Inst. Death Chance 52.00%
Damage Distribution Quick 10,20,30,40
Damage Distribution Arts 16,33,51
Damage Distribution Buster 16,33,51
Damage Distribution Extra 5,10,15,20,50
Damage Distribution NP 2,5,7,10,5,7,10,5,7,10,5,27

Attack / HP Growth

Stat Ratings

Interlude Quests

Quest Requirements Reward
Interlude 1
Chapter Completion: America

Ascension: 2

Bond: 2

Interlude 2 (ETA 2020/10)
Chapter Completion: Solomon

Ascension: 3

Bond: 5

✔ = Available ✖ = Unavailable

Ascension Materials


Skill Enhancement Materials

1 → 2 200,000
2 → 3 400,000
3 → 4 1,200,000
4 → 5 1,600,000
5 → 6 4,000,000
6 → 7 5,000,000
7 → 8 10,000,000
8 → 9 12,000,000
9 → 10 20,000,000

Total Materials Required


Costume Dress Materials

Costume Cost Materials
April Fool's 0

Bond CE

Bond Level 1 2 3 4 5 6 7 8 9 10
Bond Pts Req. 5,000 15,000 10,000 2,000 18,000 150,000 430,000 340,000 320,000 405,000
One-Man WarWhen equipped on Cu Chulainn (Alter), Increase own NP damage by 30%, and Revive with 20% HP when defeated (1 time).

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"Fall, into eternal slumber."

When Queen Medb bestowed her wish upon the holy grail for a ruthless version of the Child of Light, the result was a cold conqueror, the mad king Cu Chulainn (Alter). True to his description of being an uncharacteristic Berserker, Cu retains his incredible survivability while gaining significant Buster-based offenses from his Berserker class.

Cu Alter's high survivability is still the stuff of legends, despite his Berserker class. Coming with a two-hit Evasion in Protection from Arrows, Battle Continuation, defense buffs, as well as critical chance and attack debuffs on Madness of the Spirits, his unprecedented staying power is exceptional even when compared to non-Berserkers. What truly sets him apart from other Servants, however, is his considerable offensive power - normally unexpected from a Servant with such a defensive skill set. Thanks to a combination of an extremely high attack stat, a triple Buster deck, Madness Enhancement, and an attack buff built-in to his Noble Phantasm, Cu Alter is capable of dealing large amounts of damage over time.

These qualities, however, do not mean that Cu Alter is perfect. His deck composition means that in a team he has trouble charging his NP quickly, which makes a good support ally essential for charging his NP in time. In addition, powerful enemies with teamwide attacks or ones who can bypass his Evasion will be able to nullify a large portion of Cu Alter's high durability. Finally, his lack of direct steroids apart from his NP means he doesn't possess the on-demand performance boost of his peers, which can be problematic when damage is needed immediately.

Nonetheless, Cu Alter is an extremely powerful Berserker who can survive the most brutal enemies, and is a top performer for some of the most difficult fights in the game. For some encounters, this mad king doesn't even need allies, and will coldly destroy the enemy by himself. 

Gameplay Tip

While Cu Alter is well-suited as a general Buster Servant and can fit well into any Buster-based composition, he is also one of the most prolific solo Servants, capable of tearing up some challenging encounters all by himself. One doesn't even need to own a Cu Alter of their own to solo the appropriate fights, or raise any specific Servants in support.

All that is needed for any Servant to solo are two level 1 Servants with a taunt: generally a Leonidas and a Georgios. In Cu Alter's case, activate his Protection from Arrows, and then rotate the two taunts on turn 1 and 2, letting one Servant taunt at a time and die. On turn 3, the Servant will be alone and in Cu Alter's case, he can churn out massive damage with constant Buster Brave Chains. With the help of Mystic Codes such as the Atlas Academy Uniform, Cu Alter in particular can survive for many turns while the enemy charges his NP via his high Berserker defensive NP gain.

For Cu Alter, survival will depend on a Master's ability to rotate his Protection from Arrows, Battle Continuation, his NP, and the equipped Mystic Code's abilities to successfully survive as long as it is necessary to achieve victory. Having maxed out skill levels to reduce cooldowns is key.


Hit-Based Evasion

Protection from Arrows is one of the best defensive skills, as hit-based Evasion will not disappear until it’s fully depleted. This means that this skill will never be wasted except if Masters use it while his Evasion hits haven't yet been used up.

Defense Buff Stacking

Even when the Evasion is depleted, the additive nature of the defense buffs provided by his NP, Protection from Arrows, and Madness of the Spirits’ attack down allows him to stack enough defense buffs to protect himself until Protection from Arrows is off cooldown again.

Defensive Options

Madness of the Spirits also applies a Critical Chance Down debuff on the target, greatly reducing the risk of stray critical hits, which can be highly important against higher-tier bosses. Meanwhile, Cu Alter’s Battle Continuation skill acts as a clutch, buying time for his other skills to come off cooldown. Due to its long duration, Battle Continuation can be used early and actually come off cooldown again if timed right. This is especially potent if Cu Alter is soloing. 

High Damage

With a triple Buster deck, a high rank in Madness Enhancement, and a high attack stat, Cu Alter is able to dish out damage at any time, something further reinforced by the Berserker class’ wide range of effectiveness and 1.1x damage modifier.

Exceptional Noble Phantasm

With built-in attack and defense buffs, Curruid Coinchenn essentially functions as Cu Alter’s damage-increasing skill, allowing him to perform highly powerful Brave chains. As mentioned above, the defense buff, when used with the rest of his kit, allows him to stack defense buffs rather easily.


Inconsistent NP Gain

As with most Berserkers, Cu Alter suffers from a difficulty to create Arts chains or access his single Arts card. However, Masters can counteract this with smart usage of his hit counts as his Buster and Quick cards do generate a decent sum of NP gauge when a chain has been initiated with an Arts card. In addition, his defensive NP gain is very high thanks to his class, which is very noticeable against high hit enemies or when he is soloing. 

Lack of On-demand Steroids

As Cu Alter’s biggest damage-increasing buff is tied in to his NP, he has difficulty dealing major burst damage without external support when it is not accessible. His own naturally low star weight also makes it noticeably more difficult to support him via Critical Damage as well without an overflow of critical stars. Generally, Cu Alter grinds the opponent down over time rather than smashing them immediately. 

Vulnerable to Evasion-ignoring Enemies

Cu Alter's overall high survivability is still mainly tied up in Protection from Arrows, as his defensive buffs and debuffs only serve to partially neutralize his vulnerable Berserker typing. Enemies who strip him of buffs or can pierce his Evasion will be able to kill Cu Alter relatively quickly. 

Level Up Skill Recommendation

Skill Priority
Madness of the Spirits A

Reduces all enemies' attack for 3 turns.
Reduces their critical attack chance for 3 turns.

Show Info
Attack - 10% 11% 12% 13% 14% 15% 16% 17% 18% 20%
Crit Chance - 30% 32% 34% 36% 38% 40% 42% 44% 46% 50%
CD 8 8 8 8 8 7 7 7 7 6
Protection from Arrows C

Grants self Evasion for 2 attacks.
Increases own defense for 3 turns.

Show Info
Defense + 7% 7.7% 8.4% 9.1% 9.8% 10.5% 11.2% 11.9% 12.6% 14%
CD 7 7 7 7 7 6 6 6 6 5
Battle Continuation A

Grants self Guts status for 1 time, 5 turns.

Show Info
Revives with 1000 HP1150 HP1300 HP1450 HP1600 HP1750 HP1900 HP2050 HP2200 HP2500 HP
CD 9 9 9 9 9 8 8 8 8 7

Cu Alter often functions as the linchpin for some of the most difficult quests. Masters are therefore highly advised to invest in all of Cu Alter's skills, as the cooldown reduction often proves essential for survival. A single turn delay on Protection from Arrows may end up in Cu Alter's demise. Battle Continuation is his least potent skill however, and Masters may decide to pass on maxing it in the short term. 

  • Madness of the Spirits: While somewhat situational, the critical chance reduction at 50% maximum can be crucial for certain stages. The Attack debuff is also very potent for defense-stacking strategies, meaning that this skill also benefits greatly from having a reduced cooldown. Level this skill second.

  • Protection from Arrows: In terms of percentage scaling, the defense buff increase is rather minuscule, and the 2-hit Evasion does not directly benefit from it. The biggest reason for leveling this skill, however, is the cooldown reductions acquired at levels 6 and 10. Due to the Evasion’s nature, it would most likely be used as soon as it goes off cooldown, which makes it important to maximize this skill’s uptime. Level this first, and max it as soon as possible.

  • Battle Continuation: As a clutch tool, Battle Continuation has the least priority, as it would be used much less than the other two skills. While the HP increase is not as notable, the cooldown reduction it gets when leveled can prove to be the difference between victory and defeat.This skill can be leveled last, and is important to his solo potential as well.

Craft Essence Recommendation

With limited access to steroids of his own, the selection of Cu Alter's Craft Essence greatly impacts his performance. Luckily, Cu Alter has great synergy with a vast selection of CEs. For general performance, Buster Up (stacks better with his NP) and Attack Up (stacks better with just Madness Enhancement) work very well for use with his basic command cards and NP. In addition, Starting NP Gauge is naturally a great choice for farming or launching an NP quickly. Finally, Hit-based Invincibility and his Bond CE are both potent choices.

  • Volumen Hydrargyrum / One-Man War: Cu Alter's defense CEs of choice. Invincibility buffs actually take precedence over Evasion buffs. Essentially, this means Volumen's Invincibility is consumed before Protection from Arrows is even touched. Thus, Cu Alter can take up to 5 hits before receiving damage with Volumen, and odds are that his Evasion will be off cooldown again by then. His bond CE is a potent Guts-based alternative. 
  • Kaleidoscope / The Imaginary Element: Allows an early usage of Cu Alter’s NP with minimal effort, allowing him to take off some early pressure from the team. Best used for faster-paced boss fights or when farming.

  • Partake with the King / First Sunrise / Golden Sumo / Holy Night Supper: Combining both early-game stability and long-term benefits, all the common hybrid options are great picks for Cu Alter. 

  • Limited/Zero Over / Verdant Sound of Destruction / Victor of the Moon / Joint Recital : As Buster performance up buffs scale multiplicatively with Cu Alter’s NP’s attack buff, these options increase his overall damage significantly. The Critical Damage options are actually very viable in compositions that supply an inordinately high amount of critical stars. 

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Other Info

Release Date America Chapter Release
AKA/Alias/Nicknames Oniki, Cu Alter, Cuzilla
Country/Place of Origin Ireland
Illustrator Shimadrill
Seiyuu (CV) Nobutoshi Canna
Series Fate/Grand Order



Valentine's CE


Story-locked - Only available in the Story Summon after completing their associated Story section, or in limited banners in which they are explicitly listed as a Rate-Up Servant.

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