Keys are GFL2: Exilium's per-doll customisation layer — the thing that turns a working doll into a finished one. Key Regulation unlocks at Commander Level 15. This guide covers the four key types, how you earn them, and where to spend the upgrade materials. Every doll's own Recommended build box lists which specific keys to run on her; this page is the system reference behind it. Facts are from the game's own Key Regulation and Affinity screens, reworded; the pick advice is loadoutgg's synthesis.
The Key Regulation layout
Each doll fills a fixed set of slots: three Fixed Keys on the left, three Common Keys on the right, her Expansion Key in the centre if she has one, and — since the Deep Oblivion update — one Affinity Key.
Fixed and Expansion keys are doll-specific and do nothing on anyone else. Common and Affinity keys draw from shared pools.
You can re-slot freely at no cost, so swap keys per content — a stealth-favouring Fixed Key for Boundary Push, a boss-damage one for Boss Fight.
Fixed Keys (Exclusive Keys)
Six exist per doll; three can be active. They come from the Evolved nodes of her Neural Helix (nodes 4, 7 and 10 each offer two — you keep one) and from reaching Bond 5 with her.
They range from unconditional (start the fight with Confectance banked, a flat crit bump) to highly conditional (a bonus only when the target has a phase debuff, or an ally is below an HP threshold).
Default rule: slot the unconditional damage / resource / survival ones, then fill the third with whichever conditional key your team reliably triggers. The doll's Recommended build box marks a safe trio.
Common Keys (Universal Keys)
A shared pool of small flat-stat modules — blue keys give about +2% to two stats, purple keys about +3% to two stats plus a light conditional clause, gold keys +5% plus a stronger clause (the gold ones are the Common Key each doll drops into the pool when you finish her Neural Helix).
Sources: event shops, finishing any doll's Neural Helix, and reaching Bond 5. They're genuinely scarce — don't dismantle spares carelessly.
What to run: for damage dealers, two Attack Boost + Crit Rate purples (Heavy Metal, The Force of Bravery, Tacit Lookout, Vibrant Tremolo are all this shape). For healers and Bulwarks, Attack Boost + HP or Attack Boost + Defense. The ECG Flutter key (Attack + HP, buyable monthly from the Growth Stack) is the designated Evolution fodder.
Common Key Evolution
Purple and gold Common Keys can be Evolved, like weapon-attachment calibration. Spend Universal Chain Keys + Sardis Gold to raise the two stat rolls toward +5%.
Purple keys can then unlock one bonus stat, gold keys two — each starts at +0.5% and is upgraded separately.
Universal Chain Keys come from the weekly Platoon and Boss Fight shops, gift boxes, or dismantling Common Keys (a blue yields 40, a purple 100; gold keys can't be dismantled). Only Evolve keys you're certain you'll keep.
Expansion Keys (Peak Keys)
One per doll that has one — the kit-changer. It rewrites a skill, converts a damage type, adds a summon, or removes a drawback, and is usually a doll's biggest single power step after her signature weapon.
Unlocked with a dedicated item from an event or shop, not with raw duplicates — so an Expansion Key can land on a doll you haven't fortified.
The full list of Expansion Keys and their effects is on the Basics page; each doll's own is shown in her Recommended build box.
Affinity, Bond & the Affinity Key
Affinity (raised with Gifts in the Dormitory) grants Implicit Feedback — flat Attack / Health / Defense bonuses at each level — and unlocks story content.
Bond levels (from Affinity plus time spent) unlock a doll's Fixed Keys at Bond 5 and hand you a Common Key for the shared pool.
The Affinity Key slot holds a key whose stats scale with the doll's Affinity level — free power that grows as you raise Bond, so keep gifting your main-team dolls.
Gift priority: match a gift's category to the doll's liked categories (shown on her Dormitory screen) for full value; each doll page's flavour hints at her tastes.