Battle in New York 2024 - Challenge Guide: Giga Coil 3 - Galaxy Guardian

This battle is a straightforward single-boss fight against MHXX, a foreigner.  There are two parts to this fight.

Part One:

• MHXX starts with 315k HP and a large defense buff.

• MHXX will cast a stun (1 turn, removable) and Target Focus Up (3 turns, removable) on a random frontline Servant.

Part Two:

• On Break, MHXX will remove her defense buff but gain a large attack buff, in addition to having 1,687,500 HP.
• MHXX will cast a permanent Target Focus Up (permanent, unremovable) on a Servant.  This Servant will also deal/receive damage as if they were the Saber class.  This means MHXX's NP will do extra damage to affected Servants. Note: MHXX cannot cast this if she is stunned.
• MHXX will gain full NP gauge Every Turn.

Strategy

With sufficient damage, beating MHXX is a matter of removing her stun the first turn, bursting down her first bar with defense ignore/effective damage, and on the next turns just brute forcing her down while casting survivability.

• The optimal setup for this fight is having a main DPS buffed by supporting Servants, with a debuff cleanse from Servant or Mystic Code to get rid of the initial stun and make runs more consistent.  Hard survival is also highly recommended due to MHXX's repeated NP potential.
• Bringing a limit broken Twin Star Diva's on the main DPS and Limit Broken/extra copies of Bestia del Sol will aid in making the boss much easier.
• MHXX is a Foreigner, so don't use Berserkers against her.  Conversely, ST Alter Egos and Servants who can ignore Defense are excellent choices.
• Jack the Ripper is an excellent choice against MHXX due to her NP both ignoring defense and providing a "Damage Against Females" buff.
• Meltryllis, Sitonai, Mecha Eli - all of these are strong Alter Ego choices with sufficient support.  Meltryllis and Sitonai are notable for their looping ability and are thus more consistent than Mecha Eli due to Eli's reliance on crits for the first bar.  In all cases, remember to stun MHXX so she cannot accidentally turn an Alter Ego into a Saber and negate their offensive advantage.
• Sherlock Holmes is a flexible choice whose teamwide defense ignore opens up a lot more possibilities in teambuilding and DPS choice.  Although he can also serve as a DPS himself, the reliance on cards/crits makes it less stable than supporting another Servant with Effective damage against MHXX.
• Merlin, Skadi, and Waver are invaluable for providing high damage buffs and gauge charging, allowing faster clears.  Tamamo can work for stalling out MHXX, but needs to be paired with hard survivability.
• Asclepius is an invaluable switch-in Servant who not only provides a teamwide cleanse but also NP charge and NP Seal for the enemy.

• 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.
  • 2 turn clear ft. Holmes, Brynhild
  • 2 turn clear ft. Buster, Quick, Arts Alter Egos and meta supports+ Asclepius.