Blackthread of the Elden Sea (Canto X, Route B)

Before the 5F battle

Prepare Pierce damage and defense to reduce Tangling

• Finish shopping toward Customer Lv. 65 and Diamond rank. Yi Sang, Meursault, and Gregor are required. Prepare opportunities to use defense and HP recovery; do not rely on only one Sinner to receive “Abyssal Maw”.
• All enemy attacks are Blunt. Check Blunt resistance; offensively, use Pierce 1.2 and Wrath, Lust, Gluttony, and Pride 1.2. Slash and Blunt are 0.8; Gloom and Envy are 0.75.
• He Who Nails lets Meursault gain 2 extra E.G.O resources matching a used skill's affinity, twice per turn. Its survival effect requires another ally alive at Turn Start, so protect the other Sinners too.

Opening and during Panic

Intercept attacks on Pwie with Sinners

• The enemy starts Panicked. In that state, all targets are Pwie and all Coins become Unbreakable. Check each slot's target and clash with Sinners.
• If Pwie is the main target during Panic, Clash Power +6 and Base Power +4. Low Morale also grants +3 and +2. Distinguish the prediction while Pwie is targeted from the values after redirecting to a Sinner.
• Many skills are clashable regardless of Speed. Assign recipients with few statuses to “Abyssal Maw” and attacks that forcibly Stagger targets with at least 15 Tangling.
• Panic resets SP to 0 at Turn End, but clash losses can lower it again. Do not assume low SP means safety; check current Unbreakable Coins and targets every turn.

Each turn and when Tangling rises

Reduce Tangling and rotate dangerous clashes

• Tangling increases damage taken, lowers Base Power by 1 per 10 Stack, and applies Bind next turn per 3 Stack at Turn End. Do not keep assigning strong clashes to a heavily affected Sinner.
• Using a Defense Skill removes half the current Tangling, rounded down. The left arm's “Give It Back...” deals 90% less damage if the recipient has defense equipped, making it a useful opportunity to defend.
• When “Cleansing” appears, take a winnable clash with a Sinner carrying Tangling. Their Tangling is fully removed regardless of the result. If you win, half that part's Blackstitch remains, rounded up.
• “Abyssal Maw” reuses its Coin On Hit against Staggered targets or those with at least 20 Tangling; the reused hit deals fixed damage equal to 150% max HP. Do not rely solely on the post-clash removal of 10 Tangling; rotate to a less affected Sinner.

Attacking during the normal pattern

Focus one part and build Blackstitch

• Focus damage on the part you want to Stagger rather than spreading attacks across parts. Arms can still be attacked after destruction. Some Stagger positions are unconfirmed; check the actual gauge too.
• Each hit gives the enemy 1 Bursting Blackstitch, plus 1 more for Slash. It increases damage taken by Stack%, and grants 1 Fragile per 25 Stack at Turn Start. Slash is resisted at 0.8, so weigh Blackstitch buildup against direct damage.
• A hit from a skill with at least 5 Atk Weight grants Clumped Black Threads next turn, once per turn. It increases damage taken but also raises part slot weight. Area attacks may not reach every part; check the target display.
• Clumped Black Threads raises arm Clash Power but lowers it on the torso's “Thrashing of an Elden Being” and Tangling. Check each part's modifier, and finish necessary healing before triggering Stagger.

Part Stagger and the next turn

Clear pools with multiple Attack Skills

• When any part is Staggered, each other part loses one Stagger Threshold and the turn ends immediately. Do not plan on all remaining attacks or healing resolving.
• All parts gain Pool of Black Water next turn. They take 100% less damage, cannot be Staggered, and deal 100% more unopposed damage. Keep clashing instead of ignoring attacks, and use spare skills to reduce pool Potency.
• The pool loses 1 Potency when hit, once per skill. Check each part's remaining value and hit it with multiple Attack Skills. It also loses 1 Count at Turn End and expires when either Potency or Count reaches 0.
• A part whose pool is removed by hits gains 10 Blackstitch. If the gain exceeds the Blackstitch cap, it also gains 3 Fragile this turn and next turn. If the pool expires over time, it gains Instinct of the Predator of Eld next turn; check how it was removed.

After pools disappear: predation

Prepare for repeated Maws and damage the weakened parts

• Prepare for the predation pattern after pools expire. The torso uses four Abyssal Maws; divide clashes among multiple Sinners and avoid assigning Staggered recipients or those with at least 20 Tangling.
• Each part with Instinct of the Predator of Eld grants +2 Clash Power to all parts. Damage also increases with the recipient's Tangling. After pools expire over time, prioritize strong clashes and Tangling control.
• Parts with more Blackstitch take more damage. Focus strong attacks after the pools disappear; when the “Cleansing” Counter appears, also use it to remove Tangling.
• Damage and Stagger Threshold rise from Burn, Bleed, Tremor, Rupture, and Sinking are reduced by 50%. Do not rely on statuses alone; finish with direct skill damage too.

What to prepare first

• Aim for Customer Lv. 65 and Diamond rank. Check defense and HP recovery on the required Yi Sang, Meursault, and Gregor too.
• Build mainly around Pierce with Wrath, Lust, Gluttony, and Pride attacks. Status effects are halved, so value direct skill damage too.
• Prepare Blunt resistance and multiple clash recipients who can rotate to Sinners with less Tangling. Avoid Maw's reuse condition as well as winning its clash.

Multiple high-Power clash specialists

Intercept attacks on Pwie and handle four predation Maws while resting Sinners with high Tangling.

Focused Pierce damage and repeated skills on parts

Build Blackstitch to damage parts; use multiple Attack Skills to remove pools.

Defense and HP recovery

Reduce Tangling and heal remaining Unbreakable damage. Finish necessary healing before triggering Stagger.

One ally can fill several roles. First choose a main fighter who can win Clashes, then assign responsibilities for dangerous attacks and special mechanics.