Cu Chulainn (Prototype)

Cu Chulainn (Prototype) Discussion

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Base Atk1,315Base HP1,817
Max Atk 7,082 Max HP 10,098
Grail Atk 9,584 Grail HP 13,691

Stat Ratings

Attack / HP Growth


Proto Cu is, in essential, a much more offensive version of normal Cu Chulainn. Trading Battle Continuation and Disengage for the ability to do critical damage reliably and increased damage against Beast type enemies allow him to serve as a great budget damage dealing Lancer. Beast-trait is a quite common trait amongst frequently appeared enemies, such as Chimera, meaning Proto Cu will prove quite useful for these type of enemies and will only become more valuable as the game goes on. And while he does not have Guts, Proto Cu is still extremely tanky thanks to Protection from Arrows and is more than adequate for him to find a place in tough challenges.

Proto Cu however is not without flaws, as he has a somewhat awkward deck of BBQQA which hampers his NP generation rate while does not really contribute much to his Star generation rate either. He also does not contribute much to the team in term of buffs or debuffs, and while he is a good Servant independently, he needs heavy support to reach his full potential.


  • Hard to kill thanks to having Protection from Arrows
  • Great damage potential for a 3 Star Servants thanks to possessing both a Critical Damage increase and Star Absorbtion buff
  • Is a great choice when battling enemies with Beast trait (a quite common trait that's often found in events/daily maps)


  • Awkward card deck for NP generation combined with fairly normal NP generation rate means he often need support to get to 100% NP bar
  • Lack of Attacks or Card Performance boost to improve his NP damage output and often rely on Critical Hits to deal meaningful damage, making him more dependent on team support
  • Mediocre Star generation capability despite having a light Quick deck due to low hit count on his cards

Craft Essence Recommendation

Being a strong survivalist and critical damage dealer (once he gets his Rank Up quest), Cu Chulainn Proto appreciate any form of Quick card performance boost as well as a critical damage boost.

  • Imaginary Around / Gandr - the basic Quick card booster CEs are perfect for him as he has a light Quick deck (BBQQA)
  • Guda-O / Holy Night Sign: Craft Essences that give him two out of several stats that he want
  • Gem Magecraft: Antumbra / Knight's Dignity: For team that make Cu Proto the main Critical Damage Dealer

Level Up Skill Recommendation

Divine Protection from Arrows is the claim to fame for both Cu Chulainn and it is what gives them incredible tankiness for hard battles. Thus, you'd do a disservice not leveling it first.

Afterward, Beast Slayer is better than Rune Spell as it gives Cu Chulainn Prototype a unique niche against certain enemies. Furthermore, in the long run, it is also a great offensive skill after the Rank Up due to the crit stars absorption.

Rune Spell is his least important skill, not because it is bad, but because it isn't particularly good on him until he receives his crit star absorption component on his 3rd skill, so it should be leveled last.

Suggested Servant Synergies

  • Atalante: Atalante does more for Cu Chulainn (Prototype) than Cu Chulainn (F/SN) due to Cu Chulainn (Prototype)’s Rune Spell skill granting critical damage buffs. Additionally, in a future Rank Up quest Cu Chulainn (Prototype)’s Beast Slayer skill gains the effect of star absorption, allowing him to more consistently use the stars from Atalante. Atalante’s Quick buff also benefits Cu Chulainn (Prototype) as well, compounded with his critical damage buff.

  • Hassan of the Cursed Arm: Hassan has the benefit of being an assassin with relatively low star weight and fantastic star generation not tied to an NP. This results in more consistent crits for Cu Chulainn Prototype. Additionally, with the standard assassin deck of QQQAB, Hassan is able to easily form Quick Chains with Cu Chulainn (Prototype), and stack NP overcharge with his decently fast NP gain for more instant death chance.

  • Mata Hari: With Mata Hari’s Caster animations, she gains NP at a pretty decent rate, with an NP gain rate a small fraction below Carmilla. As such, she is able to have good uptime on her debuffs. Most importantly, her defense down on the enemy team will amplify Cu Chulainn (Prototype)’s damage combined with the occasional crit stars she generates. Although inconsistent, her universal charm will give Cu Chulainn (Prototype) time for Protection from Arrows to come off of cooldown. In addition to the debuff/charm utility, Mata Hari’s NP provides an easy NP Overcharge in an NP chain.

Interlude Quests

Quest Ascen. Bond Reward
Chapter Completion: Fuyuki
1 2
Rank Up 1
Chapter Completion: Chaldea Gate
4 0
✔ = Available ✖ = Unavailable

Servant Skills

Rune Spell B

Increases own critical damage for 3 turns.
Increases own debuff resistance for 3 turns.

Show Info
Crit Damage + 18%20.7%23.4%26.1%28.8%31.5%34.2%36.9%39.6%45%
Debuff Res + 18%20.7%23.4%26.1%28.8%31.5%34.2%36.9%39.6%45%
CD 7 7 7 7 7 6 6 6 6 5

Available from the start

Protection from Arrows B

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

Show Info
Defense + 8%8.8%9.6%10.4%11.2%12%12.8%13.6%14.4%16%
CD 7 7 7 7 7 6 6 6 6 5

Unlocks after 1st Ascension

Beast-Slayer B+

Increases own attack against Beast enemies for 3 turns.

Show Info
Attack + 40%42%44%46%48%50%52%54%56%60%
CD 7 7 7 7 7 6 6 6 6 5

Unlocks after 3rd Ascension

Beast-Slayer B++

Increases own attack against Beast enemies for 3 turns.
Increases own critical star absorption for 3 turns.

Show Info
Attack + 50%55%60%65%70%75%80%85%90%100%
Stars Absorption + 200%230%260%290%320%350%380%410%440%500%
CD 7 7 7 7 7 6 6 6 6 5

Upgrades after Rank Up Quest

Class Skills

Magic Resistance C

Increase your Debuff Resist by 15%.

Divinity B

Apply Damage Plus for yourself (Total Card Damage +180).

Noble Phantasm

Gae Bolg

Barbed Spear that Pierces with Death

Deal damage to a single enemy.

Overcharge Effect

Chance to cause instant death.
Reduces defense (3 turns).

Level 1 2 3 4 5
Damage + 1200% 1600% 1800% 1900% 2000%
Charge 100% 200% 300% 400% 500%
Defense - 10% 15% 20% 25% 30%
Death Chance 50% 62.5% 75% 87.5% 100%

Ascension Materials


Skill Enhancement Materials

1 → 2 50,000
2 → 3 100,000
3 → 4 300,000
4 → 5 400,000
5 → 6 1,000,000
6 → 7 1,250,000
7 → 8 2,500,000
8 → 9 3,000,000
9 → 10 5,000,000

Unit Info

Star Info

Star Absorption88
Star Generation12.1%

NP Info

NP Charge per Hit (%)1.08%
NP Charge when Attacked (%)4%

Hits Info

# of Hits (A)2
# of Hits (B)1
# of Hits (Q)2
# of Hits (EX)3

Traits Info

Trait 1HumanoidTrait 6
Trait 2ServantTrait 7
Trait 3DivineTrait 8
Trait 4Weak to Enuma ElishTrait 9
Trait 5Heaven or EarthTrait 10

Death Info

Instant Death Chance28.00%

Other Info

Release HistorySince Launch
AKAs/Aliases/(Fan) Nicknames Setanta, Proto Cu, Proto Lancer
AlignmentLawful Balanced
Country/Place of OriginIreland
Seiyuu (CV)Kazuya Nakai