Guide
How the kit works
Start with your Stun teammate and bring Corin in when the enemy is vulnerable. If a Chain Attack triggers, select Corin for Chain Attack: Sorry.... Hold or repeatedly press the button to extend the slash. She is invulnerable throughout the skill.
With enough Energy, use EX Special Attack: Skirt Alert (Special) and extend its slash against the target. The extension costs Energy when it connects. Corin is invulnerable during the spinning slash; during the extended slash, her Anti-Interrupt level rises and she takes 40% less DMG. Without enough Energy, Special Attack: Clean Sweep also has an extendable slash and the same DMG reduction.
Basic Attack: Wipeout has up to five hits. Extend the third and fifth slashes by holding or repeatedly pressing the button. Core Passive: Hyperfocus increases the DMG of a continuous extended chainsaw slash by 37.5%, making those extensions worth using when you have an opening.
Use Dodge: Shoo! to avoid an attack, then Dodge Counter: Nope! after a Perfect Dodge. The counter is invulnerable and its slash can be extended. At maximum Decibel Rating, Ultimate: Very, Very Sorry! gives Corin another extendable, invulnerable attack.
Build and why
The recommended disc combination is four pieces of Fanged Metal and two of Woodpecker Electro. Fanged Metal gives 10% Physical DMG with two pieces. Its four-piece effect gives the wearer 35% more DMG against a target for 12 seconds after a squad member inflicts Assault on it. Woodpecker Electro adds 8% CRIT Rate.
Hormone Punk is an alternative worth considering. Its two-piece effect gives 10% ATK, while four pieces give the wearer 25% ATK for 10 seconds after becoming active in combat. That effect can trigger once every 20 seconds.
On disc 4, choose CRIT Rate or CRIT DMG. On disc 5, use Physical DMG Bonus or Percent ATK; on disc 6, use Percent ATK. For substats, the recommended order is Percent ATK, CRIT Rate, then CRIT DMG.
Housekeeper is the first weapon choice. It gives Energy Regen while Corin is off-field, and EX Special Attack hits grant short Physical DMG stacks. Steel Cushion is another option: it gives 20% Physical DMG and 25% more DMG when hitting from behind. Cordis Germina gives CRIT Rate; at two stacks, its effect also lets Basic Attack and Ultimate DMG ignore 20% of enemy DEF. Its Electric DMG bonus does not help Corin's Physical attacks.
Leveling priority
Level Core Passive: Hyperfocus first because Corin relies on extended slashes. Next, raise Special Attack: Clean Sweep, then Chain Attack: Sorry..., followed by Basic Attack: Wipeout. Finish with Assist and Dodge, in that order.
For maximum ascension, you need 800,000 Denny, 4 Basic Attack Certification Seal, 32 Advanced Attack Certification Seal and 30 Pioneer's Certification Seal.
For all skills, you need 2,905,000 Denny, 25 Basic Physical Chip, 75 Advanced Physical Chip, 250 Specialized Physical Chip, 5 Hamster Cage Pass, 9 Finale Dance Shoes and 60 Higher Dimensional Data: Crimson Awe.
Mindscapes worth it
For a suggested damage-focused order, consider Accumulated Release first. Extended slash hits build up to 40 Charge stacks. When a listed chainsaw detonation hits, it consumes them, adding DMG equal to 3% of ATK per stack.
Atomic Smash is another upgrade to look at: EX Special Attack, Chain Attack and Ultimate hits reduce the target's Physical RES by 0.5% per stack, up to 20 stacks. Each stack lasts 5 seconds independently. Open Trauma increases Corin's DMG against a target by 12% for 15 seconds after her Chain Attack or Ultimate hits it.
Battlefield Retainer restores 7.2 Energy after a Quick Assist, Defensive Assist or Chain Attack, once every 16 seconds. Amateur Maid and Special Ops Maid each add two levels to the listed combat skills. If you are satisfied with M2, the later Mindscapes are optional.
Common mistakes
Do not release every chainsaw attack immediately. Extend the slashes when there is time to benefit from Core Passive: Hyperfocus. Against dangerous attacks, remember that the EX Special's extended slash reduces DMG taken but does not give the invulnerability of its spinning slash.
Do not expect four-piece Fanged Metal to provide its extra DMG before a squad member inflicts Assault. Also check the Attribute or faction match when building a team: a Stun teammate alone does not necessarily activate Cleanup Assistance.