Bryn2 This Servant is a limited Servant. It is only available during special summoning campaigns. When no such campaigns are active, this Servant cannot be summoned. No plans have been revealed to add this Servant to the permanent summoning pool.

This article is for Assassinicon Mysterious Heroine X. For 5★ Berserkericon, see Mysterious Heroine X (Alter).

Servant Interlude Interlude 2 Interlude 3 Dialogue Strengthen


Mysterious Heroine X

★ ★ ★ ★ ★

Japanese Name: 謎のヒロインX
ID: 86 Cost: 16
ATK: 1817/11761 HP: 1862/12696
Grail ATK: 12874 Grail HP: 13909
Voice Actor: Kawasumi Ayako Illustrator: BUNBUN
Attribute: Star Growth Curve: Linear
Star Absorption: 98 Star Generation: 25.6%
NP Charge ATK: 0.81% NP Charge DEF: 4%
Death Rate: 38.5% Alignments: Chaotic・Good
Gender: Female
Traits: Artoria, Dragon, Female, Humanoid, King, Riding, Saberface, Servant, Weak to Enuma Elish
Quickicon4  |  Artsicon2  |  Bustericon1  |  Extraicon4

Active Skills Passive Skills Noble Phantasm Ascension Skill Upgrade Bond Level Biography Trivia

Mysterious Heroine X was available for summoning during the Saber Wars Event, F/GO Fes. 2017 2nd Anniv. Lucky Bag Summoning Campaign, and one of the guaranteed SSR of 2018 New Year Campaign Lucky Bag Sumoning Campaign

Active Skills

Available from the start
Fire Support EX
Gain a delayed stun buff. If present after attacking on the next turn, has a chance to stun all enemies for 1 turn.
Level 12345678910
Stun Chance + 60%62%64%66%68%70%72%74%76%80%
Cooldown 10 98

Unlocks after 1st Ascension
Instinct C+
Gain critical stars.
Level 12345678910
Stars + 45678910111214
Cooldown 7 65

Upgrades after Strengthen, Replace Instinct
Star of Saber C++
Grants self invincibility for 1 turn. UpgradeIconText
Gain Critical Stars. UpgradeIconText
Level 12345678910
Stars + 10111213141516171820
Cooldown 7 65

Unlocks after 3rd Ascension
Galaxy Meteor Sword C
Increases own critical star generation rate against Saber enemies for 3 turns.
Increases own attack against Saber enemies for 3 turns.
Level 12345678910
Star Rate + 50%55%60%65%70%75%80%85%90%100%
Attack + 30%32%34%36%38%40%42%44%46%50%
Cooldown 8 76

Passive Skills

Riding EX
Increases damage of own Quick cards by 12%.
Cosmo Reactor A
Increases own critical star generation rate by 10%.

Noble Phantasm

Sword of Unsigned Victory
Rank Classification Type Hit-Count
A+ Anti-Unit Quick 12
Effect Deals damage to one enemy.
NP Level 1 2 3 4 5
Damage + 1200% 1600% 1800% 1900% 2000%
Overcharge Effect Deals extra damage against Saberface enemies.For more details
Charge 100% 200% 300% 400% 500%
Extra Damage + 150% 162.5% 175% 187.5% 200%

Upgrades after Interlude 3
Sword of Unsigned Victory
Rank Classification Type Hit-Count
EX Anti-Unit Quick 12
Effect Deals damage to one enemy. UpgradeIconText
NP Level 1 2 3 4 5
Damage + 1600% 2000% 2200% 2300% 2400%
Overcharge Effect Deals extra damage against Saberface enemies.For more details
Charge 100% 200% 300% 400% 500%
Extra Damage + 150% 162.5% 175% 187.5% 200%


Item 1 Item 2 Item 3 Item 4 QP
1st Assassin piece5 Qp100,000
2nd Assassin piece12 Dragon fang18 Qp300,000
3rd Assassin monument5 Dragons reverse scale2 Phoenix plume8 Qp1,000,000
4th Assassin monument12 Dragons reverse scale4 Heros proof36 Qp3,000,000

Skill Reinforcement

Item 1 Item 2 Item 3 Item 4 QP
1st Shiningassassin5 Qp200,000
2nd Shiningassassin12 Qp400,000
3rd Magicassassin5 Qp1,200,000
4th Magicassassin12 Phoenix plume4 Qp1,600,000
5th Secretassassin5 Phoenix plume8 Qp4,000,000
6th Secretassassin12 Dragon fang12 Qp5,000,000
7th Voids refuse12 Dragon fang24 Qp10,000,000
8th Voids refuse36 Octuplet twin crystals24 Qp12,000,000
9th Crystallized lore1 Qp20,000,000


Strength: B
Endurance: C
Agility: A+
Mana: B
Luck: D
NP: A++

Bond Level

Bond Level 1 2 3 4 5 6 7 8 9 10
Bond Required 3,500 8,500 7,000 6,000 2,500 292,500 360,000 340,000 320,000 315,000
Total Bond 3,500 12,000 19,000 25,000 27,500 320,000 680,000 1,020,000 1,340,000 1,655,000
Bond 10 Reward Annihilation List icon Annihilation List
When equipped on Mysterious Heroine X, all allies will inflict 20% bonus damage against [Saber] while on the field.


Unlock Description Translation
Default サーヴァントユニヴァースと呼ばれる謎の時空から来訪したストレンジャー。



A Stranger that came visiting from a mysterious dimension called Servant Universe.

Claiming to be the definitive edition of the Saber Class, an Anti-Saber Decisive Weapon that fair and square performs surprise attacks as a knight.

Code Name: A-X.

Bond 1 身長/体重:154cm・42kg

属性:混沌・善  性別:女性

Height/Weight: 154cm・42kg

Source: 2013's April Fools
Region: Servant Universe
Alignment: Chaotic・Good
Gender: Female
Going to massacre the enemy with the mysterious magic sword "Secret-Calibur".

Bond 2 「アルトリア種は宇宙のガンのようなもの。誰かが刈り取らねばならないのです。誰かが」


"The Artoria Species are like a cancer of the universe. Someone has to reap them out."

Leaving behind an expression full of bitterness, Heroine X departed from her hometown.
In her favorite machine Dun Stallion II, she dashes across the sea of stars today as well.

Bond 3 その姿はおおよそサーヴァントらしからぬラフ&スポーティな服装。


On the whole, her appearance is composed of rough & sporty garments unseemly for Servants.

The blue muffler is a symbol of courage, while the cap is there to conceal her true identity and ahoge.
It's sticking out. It's sticking out, it's really sticking out.

Bond 4 対セイバー決戦兵器として、並み居るセイバーをひたすら打倒する我はこの一聖剣に賭ける修羅モードであるが、唯一セイバーリリィに対しては心を開いた。 As an Anti-Saber Decisive Weapon, she displays a carnage mode that wagers that single holy sword for nothing but defeating all the present Sabers, but she opened her heart towards Saber Lily alone.
Bond 5 こちらにやってくるまでは古代王朝の危機を救ったり人類統合組合の内ゲバを解決したり他ユニヴァースからの侵略者たちを蹴散らしたりしていたが、そんなものは彼女にとって朝食前のデザートのようなもの。どうでもいい事なので覚えていないらしい。


Before coming here, she saved an ancient royal dynasty from a crisis, settled the internal strife of the Mankind Integration Union and routed the invaders from another Universe, but for her that is like a dessert prior to breakfast. Since they are trivial, it seems like she does not remember about them.

Until the achievement of her true, dearest wish, she shall continue to wield the Himitsucalibur. Also, no matter what, she will simply cut down the Golden Great Emperor Cosmo Gilgamesh.

Extra 誰にも打ち明けられないが、その正体はアルトリア・ペンドラゴン


She has not revealed to anyone, but her true identity is that of Artoria Pendragon.

She seems to think that everybody was tricked by her perfect disguise, but since it will turn into spoilers please keep it quiet.
For the sake of her honor as well...!