Battle in New York 2020 - Exhibition 6: Sweets Universe (Mysterious Heroine X Alter)

• Buckle down, buddies, as this is probably the longest Challenge Quest of the series.  An eating contest of endurance with MHXA, if you will.  
• There are three types of enemies: some are completely safe to eat (kill), some will buff with caveats, and some should be avoided/sacrificed to MHXA.  It's ok to not steal all the buffs - this is difficult and letting some slide may be the better play.
• For the most part, the Monsters will give the same effect to the player and MHX, with some exceptions.
• Every turn, MHXA will attempt to eat another Monster unless she is using her NP, skill sealed, or disabled.  Pre-Break she will eat them at the start of the turn (granting her at least two actions), while Post-Break she will eat them at the end of the turn (granting her at least one action).
• Post Break, MHX has a Hunger Counter where she will lose 2,000,000 HP each turn after it runs out.  It starts at 17 turns and reduces by one for each buff (Mob) that players kill. 

Strategy:

• Option 1: Brute Force - Using a Servant with strong ST looping and crit potential will allow them to just focus on MHXA as much as possible.  This will require good card RNG and killing the Stone Golem T1 in order to prevent MHXA from gaining the 5 turn DEF buff.  Although the Sitonai clear is on the rerun (with more Servants available), the general strategy should hold up.  
• Option 2: Most people clear this CQ with three 3 phases to this strategy.  Phase 1: Try to steal as many safe buffs as possible.  Phase 2: Break MHXA's bar before she can kill the enemies that will charm/stun (optional), else clear as many safe enemies as possible before breaking her bar.  Phase 3: Stall it out while continuing to steal buffs if possible, and let MHXA's HP drain from hunger do her in.  

Should I Kill X?

• Stone Golem: The Golem is necessary for Brute Force rush strats, but otherwise the Defense buff isn't noticeable because of the typical focus on other mobs instead for the first 5 turns.
• Snowman 1: Go for it - low HP and a strong Arts Buff to deny MHXA.
• Buster X: Kill this to get MHXA to kill the Helter Skelter 
• Helter Skelter: Don't Kill - having MHXA skill sealed will prevent her from killing enemies for two turns and allow more time to focus down higher hp enemies.
• Gazer: Gazer will usually appear at the same time as Basilisk, so choosing between these two, Gazer is typically better to kill since the 50% NP charge will allow players to get an NP off for some support or damage, depending on the NP.
• Basilisk: Killing both the Gazer and Basilisk if possible is nice, but it's OK to let either slide to MHXA.  Do have defense prepared, though.
• Door 1: Save an NP for the door and kill it if possible, but if abusing hard survivability letting it go in favor of killing the Spriggan will make runs safer.
• Spriggan DX: Spriggan is one of the interesting enemies where either killing it or not has a demerit.  If killing the Spriggan, the HP demerit is unremovable.  In most cases players would want a sacrificial Servant to land the killing blow.  Buff removal will only remove one effect at a time, but it can be devastating since post-break MHXA can one shot Servants after removing their hard survivability.  
• Astral Critter: DO NOT KILL.  Offenders will be instant death'd.  It even debuffs MHXA handily for you.  It's like giving her the Russian Roulette Chocolate filled with Hot Sauce that lowers her critical rate.  Great for Post-Break MHXA since she mostly kills by crits.
• Wind Book: Kill by all means to force MHXA to eat the Astral Critter.  
• Snowman 2: He usually appears with the Proto Homunculus.  Between killing him and the Proto Homunculus depends on the strategy.  Allowing MHXA to kill the Proto Homunculus will allow her to regenerate 100,000 HP per turn.  This isn't too bad of a buff provided some players will wait until MHXA's hunger counter runs out to majorly drain her HP.
• Proto Homunculus: While the defense debuff can prove fatal without hard survivability, killing the Proto Homunculus is often difficult due to its high HP, with NP's typically saved for the doors.  Kill if comfortable, otherwise it's not a big loss.
• Door 2: If the Spotter is also on field, try to kill this if possible to force MHXA to eat the Spotter.  
• Spotter: Allow MHXA to kill if possible.  This will stun her for two turns.  The HP restore isn't much of a problem due to a majority of the damage coming from hunger post break.  Pre-break her hp bar is also manageable so there isn't as much problem either.
• Demon Boar: Kill if possible - this is where debuff cleanse shines.  Low HP enemy with 30% gauge is practically free if the poison is removed.  
• Hand: Killing the Hand will also cleanse all debuffs for two turns.  While it may be worth it to have MHXA eat this, this will also cleanse the poison at the cost of a two turn charm.  This charm can be cleansed, resulting in the DPS taking no Poison damage effectively.  Reducing the Hunger Counter by two at the cost of protecting a locked DPS for one turn is a strategic gamble to take in terms of run consistency.
• Wind Book: Kill if possible, just to reduce the Hunger Counter.
• Ifreeta: Kill if possible, the burn can be cleansed.  Otherwise, with hard survival it's not too much of a problem for the team if MHXA gets buffed.  If someone uses Tomoe to amplify the burn damage on MHXA, please send me a link.
• Basilisk 2: Kill if possible, otherwise buffing MHXA's attack is not a terrible problem with hard survival.

Team Composition:

• Strong DPS - Neutral classes (Foreigner, Moon Cancer, Berserker), Rider, Archer, Saber.  These classes have strong DPS options, and will deal at least neutral damage to the most important targets.  Having a secondary DPS (ideally someone with NP charge) who can swap in and take down the Spriggan might be useful to take the HP Debuff to deny MHXA buff removal.  
• Hard Survivability - Dodges and Invincibility is necessary at the end since MHXA can oneshot defense buffed Servants post-break.
• Stun/Charm - Servant Charm/Stuns are extremely useful since Post-Break Bar it's a matter of stalling out MHXA, making disables as useful as teamwide hard survivability.
• Debuff Cleanse - Unlike many Challenge Quests, many of the Debuffs are actually removable.  This allows Servants to take some of the later buffs with less consequences.  

Recommended Mystic Code:

• Chaldea Combat Uniform: The stun is one of the strongest effects in this Challenge Quest.  Combined with the ability to swap in another Taunter, this Mystic Code is one of the best at controlling the fight.
• Atlas Academy Uniform: Debuff Cleanse is great for removing certain disables while the Cooldown Reduction is great for Servants who have crucial stall or burst skills.  The targeted Invincibility may not be as good as a stun on MHXA, but can be used effectively during the last turns with one character left standing.  

Recommended CE's:

• Grudge Match: Having an MLB Grudge match will make the stage much easier in terms of doing enough damage to control which buffs are stolen.
• Volumen Hydragyrum/Under the Sun: The three hits of damage negation can especially help taunters survive an extra turn with Post-Break MHXA's one shot potential.
• Fragments of 2030: Stars per turn on support-defensive Servants are always useful for more potential crits, which will allow the DPS to take down priority targets without NP's.  
• Prisma Cosmos:  NP gain/turn will allow supports like Jeanne or Skadi to have their NP up more often, and make the Arts chains more consistent.

• Note that these videos are not affiliated with GamePress, but showcase some lineups that are effective in clearing the final challenge. These can serve as a good reference for how to rotate skills during this quest or simply to have a look at the encounter before diving in.
  • BB/Jeanne Clear
  • Hokusai/Avicebron Clear
  • 500 IQ Hijikata Clear
  • Cu (F/SN) Clear (2x MLB CE)
  • Abigail/Jeanne Clear
  • Sitonai (Rerun, for reference) Clear