For an Attack DPS, the order is short: CRIT Rate and CRIT DMG first, ATK% second, everything else a distant third. For an Anomaly agent, swap in Anomaly Proficiency near the top and drop CRIT down the list. That single sentence solves most of the substat question. The rest of this guide is why it is true, how the roll math works, and the one rule that stops you from pouring materials into a disc that was never going to pay off.
The main stats and set bonuses are covered in our Drive Discs and W-Engines guide. This one is only about the four small lines underneath, because that is where two identical-looking discs turn out to be worlds apart.
How substats actually roll in ZZZ
A Drive Disc has one main stat and up to four substats. An S-rank disc caps at level 15, and it gains an upgrade every three levels, so at levels 3, 6, 9, 12, and 15 the disc rolls once. That is five upgrades total across a disc's life.
Where those five upgrades land depends on how the disc dropped:
- A disc that drops with three substats spends its first upgrade (level 3) adding a fourth substat, then distributes the remaining four upgrades among those four lines.
- A disc that drops with four substats already has all its lines, so all five upgrades enhance the existing four.
The critical part: substat values are static. When a line gets upgraded, it always increases by the same fixed amount for that rarity. There is no low-roll or high-roll lottery on the number itself. The only randomness is which of your lines the game chooses to upgrade. So a "good" disc is not one that high-rolled; it is one where the upgrades happened to pile into the substats you actually wanted.
One more rule that trips people up: a stat cannot appear as both main stat and substat on the same disc. If your main stat is ATK%, that disc will never roll ATK% as a substat, which quietly changes what a "perfect" disc even looks like per slot.
The substat priority, by role
Discs I, II, and III have fixed main stats (flat HP, flat ATK, flat DEF), and discs IV, V, and VI carry your chosen main stat. Regardless of slot, these are the substats worth chasing:
Attack / crit-scaling DPS (most Attack and Stun agents):
- CRIT Rate
- CRIT DMG
- ATK%
- Penetration (only for agents whose kit specifically wants it)
- Flat ATK as a weak filler
Anomaly agents (built around applying and detonating elemental buildup):
- Anomaly Proficiency
- ATK%
- CRIT Rate / CRIT DMG only if the agent also crits on their hits, otherwise skip
- Flat ATK filler
Stun / support agents care mostly about their function (impact, energy, or buff uptime), so read their kit, but ATK% and the two CRIT lines still matter for any of them that contribute damage.
Notice what is missing: HP and DEF lines are dead weight on nearly every damage build. A disc that rolls three upgrades into flat HP is not unlucky, it is scrap.
The CRIT ratio you are aiming for
The rule of thumb for crit-based agents is a 1 to 2 ratio of CRIT Rate to CRIT DMG. Every point of Rate is worth roughly two points of DMG in raw output, so you balance them rather than stacking one. The practical target is to push effective CRIT Rate to around 80% or higher once you fold in your W-Engine, set bonuses, and the agent's own passives, then let CRIT DMG climb as high as the discs allow.
Do not chase 100% CRIT Rate. Past the point where your buffs and rotation reliably crit, extra Rate is wasted, and those roll slots would have done more as CRIT DMG or ATK%. Aim for consistency, not a perfect number.
When to keep a disc, and when to scrap it
Here is the rule that saves the most materials. Level a promising disc to level 9 first, not straight to 15. By level 9 the disc has taken three of its five upgrades, and you can read where it is heading:
- Two or more upgrades in your priority substats by level 9 means the disc is worth finishing. Take it to 15.
- One upgrade, or none, in your priority substats by level 9 means it is almost certainly a dud. Stop, and feed it to level a better disc.
Leveling is not free. Each attempt costs Dennies and disc EXP that your stamina had to farm, so scattering upgrades across half-built discs is the single most common way new accounts stall. The stop-at-9-and-read habit is what separates an efficient farmer from someone drowning in level-6 discs that never became anything. Manage that stamina deliberately with our battery and stamina guide, because disc farming is where most of it goes.
Putting a real build together
A finished disc set for an Attack DPS might look like: the right four-piece and two-piece set bonuses, CRIT-oriented main stats on discs IV to VI, and substats where at least your best two or three discs landed multiple rolls into CRIT and ATK%. You will not get there in a week. Substat farming is a months-long background grind, which is exactly why it inspires its own particular flavor of despair, chronicled in our piece on the substat farming grind.
The payoff is real, though. Two agents with the same characters, weapons, and disc sets can differ by 40% or more in damage purely on substat quality. That gap is the reason a serious account keeps farming discs long after the "build" is technically done.
For the rest of the picture, pair this with the agent stats and attributes guide to understand what each number does, the leveling material priority guide so you build the right agents first, and the ZZZ tier list to make sure the agent you are decking out in perfect discs is worth the investment. Grab the latest ZZZ codes too; every free Polychrome is a little more stamina toward the disc grind.
