Cu Chulainn (Alter)

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
Stat Ratings

Cu Alter is a Servant most notable for the high survivability he possesses despite his Berserker class. Coming with a two-hit Evasion, Battle Continuation, defense buffs, as well as critical chance and attack debuffs, 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 skillset. Thanks to a combination of high attack stat, a triple Buster deck, and an attack buff built-in to his Noble Phantasm, Cu Alter is capable of dealing large amounts of damage in short periods of time.

These qualities, however, do not mean that Cu Alter is perfect. His deck composition means that he would have a harder time performing Arts chains, which, in turn, makes a good support ally necessary. He is also unsuited for the role of a critical damage dealer due to the low Berserker star absorption rate, which limits his burst damage potential.


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.

Defense Buff Stacking

Even when Evasion is depleted, the defense buff provided, when combined with his Frenzy of Spirits’ attack down and NP’s defense buff, allows him to stack notable amounts of defense.

Defensive Utilities

Frenzy of Spirits also applies a critical chance 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.

High Damage

With a triple Buster deck and 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. This may severely hamper his NP gain, especially with unfavorable card distribution.

Reliance on Noble Phantasm

As Cu Alter’s biggest damage-increasing buff is tied in to his NP, he would have a harder time dealing major amounts of damage without it. In relation to his inconsistent NP gain, the effort spent to fill his NP gauge often means not using his Buster cards, reducing his overall damage.

Unsuited for Critical Damage

Due to his low star absorption, Cu Alter is unable to gather critical stars reliably.

Craft Essence Recommendation
  • 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.

  • Halloween Princess: Combining both early-game stability and long-term benefits, Halloween Princess allows Cu Alter to start off more easily, while still giving him an increase in overall damage. However, its early game phase is less reliable compared to the preceding Craft Essences, meaning that support-type allies should be brought along.

  • Limited/Zero Over/ Verdant Sound of Destruction: As Buster performance up buffs scale multiplicatively with Cu Alter’s NP’s attack buff, these increase his overall damage significantly. However, a fully supportive team would be needed in order to aid in his NP gain.

Level Up Skill Recommendation
  • Protection from Arrows C: In terms of percentage scaling, the defense buff 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.

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

  • Battle Continuation A: 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.

Servant Skills
Madness of the Spirits A

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

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.

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.

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)

Increases Buster card effectiveness by 6%.

Divinity C

Increase damage dealt by 150.

Noble Phantasm
Curruid Coinchenn
Beast of Crunching Death Fangs

Deal significant damage to a single enemy

Overcharge Effect

Increases own attack and defense (1 turn)

Level 1 2 3 4 5
Damage + 600% 800% 900% 950% 1000%
Charge 100% 200% 300% 400% 500%
Attack + 30% 40% 50% 60% 70%
Defense + 30% 40% 50% 60% 70%
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
Unit Info
Star Info
Star Absorption9
Star Generation5.1%
NP Info
NP Charge per Hit (%)0.69%
NP Charge when Attacked (%)5%
Hits Info
# of Hits (A)3
# of Hits (B)3
# of Hits (Q)4
# of Hits (EX)5
Traits Info
Trait 1HumanoidTrait 6Weak to System Keuranos
Trait 2ServantTrait 7Evil
Trait 3DivineTrait 8
Trait 4Brynhildr's BelovedTrait 9
Trait 5Weak to Enuma ElishTrait 10
Death Info
Instant Death Chance52.00%
Other Info
Release HistoryAmerica Chapter Release
AKAs/Aliases/(Fan) NicknamesOniki, Cu Alter
AlignmentChaotic Evil
Country/Place of OriginIreland
Seiyuu (CV)Nobutoshi Canna
SeriesFate/Grand Order