Mysterious Heroine X

Mysterious Heroine X Discussion

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Base Atk1,817Base HP1,862
Max Atk 11,761 Max HP 12,696
Grail Atk 12,874 Grail HP 13,909

Stat Ratings

Attack / HP Growth


On paper, MHX has a strong statsline. She has good attack for an Assassin, high NP Generation, and good Star Generation rate, along with a single target Noble Phantasm that has early Interlude boost. However, she is a complete disappointment in terms of her skills. Her skillset is so bad that it is essentially playing without any skills the majority of the time when using her, and you are better off treating her like a literal stat stick instead of a fully fledged Servant.

Starting with Fire Support; it has an extremely high cooldown, a one-turn delay (so you have to plan ahead when attacking) and even then its stun chance isn't even guaranteed, making it a nonfactor in a lot of fights due to its downtime and general unreliability. Instinct is pretty much a mediocre skill, although MHX does get a Rank Up quest later turning this skill into an invulnerability buff for one turn, which does a lot for her survivability. And last but not least it's her Galaxy Meteor Sword, which only works against Saber enemies (who you're better off just bringing Archers against instead for the bonus damage and damage reduction at all times). Her Noble Phantasm's overcharge effect is also quite terrible, as it hits a very specific subset of Servants and is pretty much worthless compared to other Servant's Overcharge effects.

All in all, MHX stats are good enough for her to function as a decent single-targeted Assassin, but due to how terrible her skillset is in general, setting your expectation a bit lower when using her would be reasonable.


  • Great NP generation thanks to a BAAQQ cards deck, high hits count on her Quick cards with Riding boost and high NP gain per hit
  • Good critical stars generation thanks to having high hits count Quick card and Quick NP, with two passive that boost Star Generation rate in Cosmo Reactor and Riding
  • High single target damage Noble Phantasm due to early access to her NP up Interlude and high base Attack


  • Terrible skillset all around:
    • First skill is unreliable and has high cooldown
    • Second skill is mediocre until Rank Up buff
    • Third skill is extremely niche and rarely finds its use
  • Niche Noble Phantasm's overcharge effect that is irrelevant most of the time
  • Lack of strong  and reliable steroids to boost damage output in general

Craft Essence Recommendation

  • Imaginary Around / Gandr / Holy Night Sign: Since MHX does not have any Quick performance buff outside of Riding but is quite reliant on it, these CEs will help her tremendously in everything she does
  • Guda-O / Knight's Dignity / Gem Magecraft: Antumbra: Due to her star generation capability, a Critical Damage boosting CEs will do a lot of good for her as she will frequently do Critical Attacks

Level Up Skill Recommendation

None of MHX's skills stand out. After her Rank Up her second skill turns into a very good survival skill, but until then each skill is somewhat equal in their value. 

Fire Support can be levelled if a Master wants more reliability from the stun effect. The cooldown remains too long for it to be used multiple times per fight. 

Levelling Intuition will only add a rather small amount of stars, even at max rank. The cooldown reduction is quite useful however, and after Rank Up, makes MHX one of the very rare Servants with an Invulnerability on a 5 turn cooldown. 

Galactic Metor Sword is quite powerful but affects only Sabers. For Masters intending to use MHX against Sabers this skill can be levelled first. 

Interlude Quests

Quest Ascen. Bond Reward
Interlude 1
Chapter Completion: London
1 3
Interlude 2
Chapter Completion: London
2 4
Interlude 3
Chapter Completion: London
3 5
✔ = Available ✖ = Unavailable

Servant Skills

Fire Support EX

Gains a delayed buff.
After 1 turn, chance to Stun all enemies for 1 turn.

Show Info
Stun Chance 60%62%64%66%68%70%72%74%76%80%
CD 10 10 10 10 10 9 9 9 9 8

Available from the start

Unlocks after 1st Ascension

Star of Saber C++

Grants self Invincibility for 1 turn.
Gains critical stars.

Show Info
Stars + 10111213141516171820
CD 7 7 7 7 7 6 6 6 6 5

Unlocks after Rank Up Quest (not available, ETA 2019/08), replaces Intuition C+

Galactic Meteor Sword C

Increases own critical star generation rate against Saber enemies for 3 turns.
Increases own attack against Saber enemies for 3 turns.

Show Info
Star Rate + 50%55%60%65%70%75%80%85%90%100%
Attack + 30%32%34%36%38%40%42%44%46%50%
CD 8 8 8 8 8 7 7 7 7 6

Unlocks after 3rd Ascension

Class Skills

Riding EX

Increase your Quick Card effectiveness by 12%.

Cosmo Reactor A

Increase your Critical Star Drop Rate by 10%.

Noble Phantasm

Secret Calibur

Sword of Unsigned Victory

Deals damage to one enemy.

Overcharge Effect

Deals extra damage against Saberface enemies.

Level 1 2 3 4 5
Damage + 1200% 1600% 1800% 1900% 2000%
Charge 100% 200% 300% 400% 500%
Extra Damage + 150% 162.5% 175% 187.5% 200%

Secret Calibur

Sword of Unsigned Victory

(Upgrade via Interlude 3.)
Deals damage to one enemy

Overcharge Effect

Deals extra damage against Saberface enemies.

Level 1 2 3 4 5
Damage + 1600% 2000% 2200% 2300% 2400%
Charge 100% 200% 300% 400% 500%
Extra Damage + 150% 162.5% 175% 187.5% 200%

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 Absorption98
Star Generation25.6%

NP Info

NP Charge per Hit (%)0.81%
NP Charge when Attacked (%)4%

Hits Info

# of Hits (A)2
# of Hits (B)1
# of Hits (Q)4
# of Hits (EX)4

Traits Info

Trait 1HumanoidTrait 6Arthur
Trait 2ServantTrait 7
Trait 3RidingTrait 8
Trait 4DragonTrait 9
Trait 5SaberfaceTrait 10

Death Info

Instant Death Chance38.50%

Other Info

Release HistorySaber Wars Event
AKAs/Aliases/(Fan) Nicknames MHX, Saber Killer
AlignmentChaotic Good
Country/Place of OriginOuter Space
Seiyuu (CV)Ayako Kawasumi
SeriesBack Alley Satsuki (4/1 Joke)