Illya's Karakuri Castle - Challenge Guide

Enemy Layout

Requirements: Clear Main Quests, unlocks on ~Day 8.

Boss Statistics

Overview

• A face off against Britomart, champion of the Chaldea Tam Lin Cup! This battle features a gimmick based around a Weak Point system, which Masters can exploit to help clear the battle quickly.
• With enough damage, it can be possible to ignore this mechanic and clear this in 3 turns, although this generally requires a high end damage dealer Servant and strong supports.
• Note this battle ends when Britomart's 2nd HP Bar is broken. She does not need to have her final HP bar depleted; she automatically withdraws after the 2nd break.
• Britomart starts with 5-time unremovable Damage Cut by 500, gains 1 extra NP Gauge each turn (will NP every 2 turns if left undisturbed), and starts with an extra 5,500,000 HP! She also has 500% Debuff Removal Resist. All these effects are unremovable.
• All Party Members and enemy Britomart will start with a Weak Point buff, which appears as a trait buff.
• Masters can damage Britomart's Weak Points the following ways:
• All party members have a passive Charge Shot buff, which allows them to gain a Power Loading buff stack so long as they don't use any attacks for a turn.
• Power Loading has a 50% chance of removing a Weak Point from the enemy when a Servant with the buff attacks.
• Choosing not to attack for two turns will give two stacks of Power Loading, making it a 100% chance of removing a Weak Point when attacking.
• Britomart can damage the party's Weak Points the following ways:
• Britomart's NP summons a random Servant that will use their NP which destroys Weak Points. The NP has several possibilities:
• 10% chance of Odysseus: Removes defensive buffs before dealing AoE damage.
• 30% chance of Minamoto-no-Tametomo: Applies Ignore Invincible + Ignore DEF before dealing AoE damage, bonus Anti-Lawful damage.
• 30% chance of Charles Babbage: Deals AoE damage, debuffs DEF after damage.
• 30% chance of Mecha Eli-chan Mk.II: Removes defensive buffs before dealing ST damage.
• After 1st break, Britomart's normal attacks will destroy Weak Points for 3 turns.
• Both Britomart and Masters can prevent Weak Point damage with the following:
• Having an active DEF buff or Damage Cut buff prevents Weak Points from being damaged.
• Consequences of Weak Point damage are as follows:
• Britomart - If all her Weak Points are damaged, she takes 2,000,000 damage every turn. It is entirely possible to clear this encounter with a stall-oriented party and no primary damage dealer due to this effect.
• Party Members - If Weak Points for a party member are damaged, they will be inflicted with three unremovable debuffs:
• Normal Attack Seal (cannot use normal Card attacks)
• Damage Resist Down by 60%
• Defensive Buff Success Rate Down by 60%
• After 1st break, on top of being able to damage Weak Points with her normal attacks, Britomart restores 3 new stacks of Weak Points for herself.
• The party has no way to restore Weak Points, although they can prevent them from being damaged via using DEF / Damage Cut buffs.

Team Recommendations

• Masters have two options that are both effective for a team lineup to take on Britomart:
• Classic damage dealer lineup - simply burst down Britomart
• Stall oriented lineup with no damage dealer - use weak point's 2 million damage over time effect to defeat Britomart
• ST Damage Dealers with Class Advantage are good choices for this battle if taking the first route. Either Saber, Beast, Pretender, or Berserker damage options are good choices.
• Stun, NP Drain, or NP Seal Support are decent choices if going for the stall-oriented strategy instead. Be cautioned, though, Britomart has a small chance of using a Debuff Immune skill (gives her 3 turns of debuff immunity), so Masters will want to setup a team that can stun lock her until her Weak Points are removed. This is particularly important during her 2nd HP Bar, where Masters must contend with removing 3 of Britomart's Weak Points. A video link below showcases the stun strategy.
• DEF Buff Support is helpful to protect the party's Weak Points. Every turn a DEF or Damage Cut buff is active, a 1-time, 1-turn protection against Weak Point damage is applied.
• Waver / Zhuge Liang is a particularly helpful ally for this fight, since he provides both the NP Drain effects and party DEF support.

• The Event Damage CE Manor of Repose should be equipped on the damage dealer (if a damage dealer is used) to maximize their damage potential!
• NP Gauge and Damage Support for the damage dealer is helpful as always to clear the waves ASAP and minimize the number of support skills enemies can use. The usual suspects of Castoria, Tamamo, Koyanskaya, Oberon, Skadi/Ruler, Merlin, Reines, and Waver are all great choices.

Video Links

• 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.
• High end Arjuna Alter Lv120 NP5 w/ Carmilla Rider, 2x Koyanskaya, Mata Hari, Skadi Ruler (3 turns)

• Draco NP3 w/ Lady Avalon, Tamamo, 2x Castoria, Chen Gong (6 turns)
• Stall setup: Lv25 Chen Gong, Waver, Castoria, Lv55 Georgios, Lv55 Phantom of the Opera, Oberon (11 turns)
• Stall setup 2: Oberon, Lv1 Caligula, Oberon, Lv1 Georgios, BB, Caster of Okeanos (13 turns)
• Stall setup 3: Prince of Lan Ling, Waver, Tamamo, Lv1 Georgios, Lv1 Leonidas (13 turns)

Quick Servant Suggestions