Guide
How the kit works
Before combat, Wail, Death's Herald puts Castorice into Netherveil for 20 seconds. Attacking enemies in range starts combat, summons Netherwing and deploys Lost Netherland. Netherwing starts with HP equal to 50% of maximum Newbud, while the other allies lose 40% of their current HP. If Netherwing is not summoned on entry, Castorice gains 30% of maximum Newbud instead.
Without Netherwing, use Silence, Wraithfly's Caress to consume 30% of all allies’ current HP and hit one enemy plus adjacent targets. Desolation Across Palms converts each point of HP allies lose into one Newbud. It also increases Castorice’s and Netherwing’s damage by 20% per stack, up to three stacks for three turns.
At maximum Newbud, Doomshriek, Dawn's Chime summons Netherwing and advances its action by 100%. Lost Netherland lowers all enemies’ All-Type RES by 20%. Netherwing disappears after three of its turns or when its HP reaches zero, removing the Territory.
While Netherwing is present, Boneclaw, Doomdrake's Embrace replaces the regular Skill. It consumes 40% of the other allies’ current HP and launches a Joint ATK against all enemies. Ally HP loss now restores Netherwing’s HP instead of generating Newbud through the Talent. Healing allies also converts into Newbud or Netherwing’s HP, with a per-ally conversion limit that resets after any unit acts.
Use Breath Scorches the Shadow repeatedly during Netherwing’s turn: each use costs 25% of its Max HP and raises the attack’s multiplier up to 34% of Castorice’s Max HP. At 25% HP or less, using it triggers the effect of Wings Sweep the Ruins. That effect also occurs when Netherwing disappears, dealing six random-target hits and healing all allies.
Build and why
Use four pieces of Poet of Mourning Collapse. Its two-piece bonus gives 10% Quantum DMG, while the four-piece effect lowers SPD by 8% and gives CRIT Rate based on SPD before battle. Below 110 SPD it gives 20% CRIT Rate; below 95 it gives 32%. The bonus also applies to the memosprite.
Pair it with Bone Collection's Serene Demesne for 12% Max HP. At 5,000 Max HP or more, it also gives Castorice and her memosprite 28% CRIT DMG. Arcadia of Woven Dreams is another planar option: it increases their damage when the number of allied targets on the field is not four.
The recommended main stats are CRIT DMG on the body, HP Percentage on the feet and rope, and Quantum DMG Boost or HP Percentage on the sphere. For substats, look for CRIT Rate first, then CRIT DMG and HP Percentage. Max HP supports Castorice’s damage and helps reach the planar set’s threshold.
Make Farewells More Beautiful is the first weapon choice. It gives 30% Max HP and lets Castorice and Netherwing ignore 30% DEF after the wearer or memosprite loses HP during their own turn. The Flower Remembers is a strong alternative with CRIT DMG for both; Sweat Now, Cry Less gives CRIT Rate and boosts their damage while Netherwing is present.
Leveling priority
Follow the game’s order: Desolation Across Palms, Claw Splits the Veil, Mooncocoon Shrouds the Form, Silence, Wraithfly's Caress, Doomshriek, Dawn's Chime, then Lament, Nethersea's Ripple. The Talent starts the Newbud cycle, while the next two upgrades cover Netherwing’s attack and its protection for allies. The Basic comes last.
For maximum ascension, gather Credit, Darkveil Moonlight, Ethereal Omen, Echoing Wail and Eternal Lament. Skill upgrades also need Credit, Tracks of Destiny, Bīja of Consciousness, Seedling of Manas, Flower of Ālaya and Auspice Sliver, as well as more of the three Omen, Wail and Lament materials.
Eidolons worth it
Crown on Wings of Bloom is worth considering for its change to the rotation. Summoning Netherwing grants two stacks that can offset the HP cost of Breath Scorches the Shadow and advance Castorice’s action by 100%. Her next enhanced Skill also grants 30% of maximum Newbud.
Await for Years to Loom is another major option: Castorice and Netherwing gain 20% Quantum RES PEN when dealing damage, Netherwing’s attacks reduce Toughness regardless of Weakness Type, and Wings Sweep the Ruins gains three extra hits. Snowbound Maiden, Memory to Tomb is a smaller option that increases specified attacks’ damage against enemies at or below 80% and 50% HP.
If you want to limit investment, consider stopping before E3. E3 and E5 raise skill levels, while E4 increases healing received by allies. You must still unlock them on the way to E6.
Teams
Castorice gives the group a 20% All-Type RES reduction while Lost Netherland is active. Netherwing also grants allies 10% damage for three turns when summoned and heals them when it disappears.
Common mistakes
Do not ignore the team’s HP just because Netherwing can protect allies at 1 HP. Once an ally reaches that floor, Netherwing bears further HP loss at 500% of the original value, so it can disappear sooner.
Do not expect ally HP loss to generate Newbud through the Talent while Netherwing is present. It restores Netherwing instead. Also check SPD before battle when using Poet of Mourning Collapse; missing a threshold changes its CRIT Rate bonus.
