Starlight - Billy Build: Drive Discs & Stats (ZZZ)

Starlight - Billy is an S-rank Rupture agent in Zenless Zone Zero. This Starlight - Billy Drive Disc build lists the sets, main stats and substats to aim for, and the Area Patrol stage that drops them, as of version 3.2.

4-piece: Yunkui Tales
2-piece: CRIT Rate +8%, CRIT DMG +16%, Physical DMG +10% or ATK +10%
Disk 4: CRIT Rate or CRIT DMG or HP%
Disk 5: Physical DMG%
Disk 6: HP%
Substats: CRIT Rate > CRIT DMG > HP%
W-Engine: Starlight Rider Faceplate
Farm at: Words and Weapons

Best Drive Disc sets for Starlight - Billy

Starlight - Billy's 4-piece set is Yunkui Tales. No other 4-piece set is recommended, so there is no substitute worth farming.

Yunkui Tales Best in slot

4-piece: When using EX Special Attack, Chain Attack, or Ultimate, CRIT Rate increases by 4%, stacking up to 3 times and lasting 15s. Repeated triggers reset the duration. When having 3 stacks of this effect, Sheer DMG increases by 10%

2-piece: HP +10%. Drops from Words and Weapons.

2-piece options

For the 2-piece slot the bonus matters, not the set's name. Several sets share the same 2-piece bonus, so Starlight - Billy can take it from whichever one you have spare pieces of:

CRIT Rate +8%: Woodpecker Electro
CRIT DMG +16%: Branch & Blade Song
Physical DMG +10%: any of Fanged Metal or White Water Ballad (they give the same bonus)
ATK +10%: any of Hormone Punk or Astral Voice (they give the same bonus)

Starlight - Billy main stats: Disk 4, 5 and 6

Disks 1 to 3 always roll HP, ATK and DEF as their main stat, so the choice is on 4, 5 and 6. A > means "better than"; = means the two are about as good.

Slot	Main stat, best first
Disk 4	CRIT Rate = CRIT DMG = HP%
Disk 5	Physical DMG% > HP%
Disk 6	HP%

Starlight - Billy substat priority

Roll for CRIT Rate and CRIT DMG first. A disc showing neither of those is rarely worth levelling for Starlight - Billy, whatever else it has.

CRIT Rate
CRIT DMG
HP%
Flat HP
Flat ATK

Where to farm Starlight - Billy's Drive Discs

Yunkui Tales drops from the Words and Weapons Area Patrol stage. The other set it drops, King of the Summit, is not part of Starlight - Billy's build.

Area Patrol stage	Sets it drops
Words and Weapons	Yunkui Tales (best 4-piece) King of the Summit (not in this build)
Fist and Gun	Hormone Punk (2-piece option) Fanged Metal (2-piece option)
Monster Duet	Branch & Blade Song (2-piece option) Astral Voice (2-piece option)
Tower and Cannon	Woodpecker Electro (2-piece option) Soul Rock (not in this build)
Deceits and Bulwarks	White Water Ballad (2-piece option) Shining Aria (not in this build)

Building more than one agent? The Area Patrol Recommender ranks every stage for your whole team at once, and the Drive Disc Stat Guide says which drops to keep while you farm.

Starlight - Billy W-Engine and skill priority

Starlight Rider Faceplate S-rank, HP sub-stat

Billy's signature is his best option by a wide margin, all the more valuable because Rupture Agents have few good alternatives. HP% mainstat, unconditional CRIT Rate and a stacking Sheer DMG buff give him exactly what he needs.

Skills to level first

Chain Attack
Special Attack
Basic Attack
Assist
Dodge

Agents who also use Yunkui Tales

These agents compete with Starlight - Billy for the same set, which is worth knowing before you hand a good piece to one of them.

Check the discs you already have

Hundreds of discs in the inventory and no idea which ones Starlight - Billy could use? Drive Disc Triage reads an export of your account and sorts every disc into lock or discard, checking each one against this build and every other agent you own.

Open Drive Disc Triage

Questions

What is the best Drive Disc set for Starlight - Billy?

Yunkui Tales 4-piece. For the 2-piece, any set with CRIT Rate +8%, CRIT DMG +16%, Physical DMG +10% or ATK +10% works.

What main stats should Starlight - Billy use on Disk 4, 5 and 6?

Disk 4: CRIT Rate = CRIT DMG = HP%. Disk 5: Physical DMG% > HP%. Disk 6: HP%. Disks 1 to 3 have fixed main stats (HP, ATK and DEF), so only their substats matter.

What substats does Starlight - Billy need?

In priority order: CRIT Rate, CRIT DMG, HP%, Flat HP, Flat ATK. The first two are what make a disc worth levelling for Starlight - Billy; the rest are tiebreakers.

Where do I farm Starlight - Billy's Drive Discs?

Yunkui Tales drops from the Words and Weapons Area Patrol stage, alongside King of the Summit. Each run at Lv.60 costs 60 Battery Charge and splits its S-rank discs between the two sets.