The best Anby build in Zenless Zone Zero is all about stunning enemies as fast as possible. The stun agent specialisation is perhaps the simplest in the game; they hit enemies hard, accumulating daze, and triggering a stun so you can chain attack with your other squad mates for extra damage. While stun characters do a bit of damage themselves, it's not their primary focus and that stuff is better left to an attack character.
Anby's playstyle is also absurdly simple. After the third attack in her combo, you either hold or input the next attack late to activate a Thunderbolt, dealing increased daze and electric damage. Pulling off a Thunderbolt also lets Anby activate her special attack faster for even more daze.
It can be a slightly annoying playstyle at times if you're struggling to get the full combo off before having to dodge or counter, but Anby's stun capability makes her a handy early-game character, especially if you don't pull another stun agent like Lycaon or Koleda. Here's my best ZZZ Anby build plus what you need to level her lower down the page.
Since she's a stun agent, Anby is pretty straightforward. She hops in and smacks about enemies, accumulating daze until they're stunned, allowing you to trigger a chain attack with your other squad members.
If you hold the attack input after the third strike in her combo, she performs a special Thunderbolt attack with electric damage and increased daze. As such, you'll primarily want to boost Anby's impact so she stuns enemies quickly.
The S-tier The Restrained is undoubtedly the best W-Engine for stun characters, since it buffs the damage and daze dealt by basic attacks by 6%, stacking up to five times. This activates for eight seconds whenever you hit an enemy. Since Anby's Thunderbolts count as basic attacks and already deal increased daze, you can see why this would be so strong for her.
In terms of alternatives, the A-tier Demara Battery Mark II is a good choice as well, increasing electric damage by 15% and providing energy regen whenever she performs a dodge counter or assist attack. Considering Anby's additional ability provides energy when her dodge counter hits enemies, this essentially just boosts that effect.
For Drive Discs, I recommend the stun-focused Shockstar Disco set. Two-pieces buffs impact by 6%, while four-pieces increase the daze dealt by basic attacks, dash attacks, and dodge counters. Both of these effects will help you stun enemies far faster. After that, I suggest two-pieces of Thunder Metal for their 10% electric damage bonus.
You can get Shockstar Disco and Thunder Metal from the Hunter and Hound Cleanup activity. You can also grab them from the Bardic Needle store on Sixth Street. Both of these will unlock after you complete the Belobog commission as part of the main story.
In terms of base stats on the Drive Discs, I recommend:
I'd suggest attack on Drive Disc 4 simply to make Anby hit harder, but anomaly proficiency is also an option if you'd prefer to deal damage by applying Shock to enemies with her electric attacks. The reason I don't recommend that as much is because you'll want impact on Drive Disc 6 instead of anomaly mastery. Anomaly mastery buffs how quickly you apply attribute anomalies and isn't a stat you can get anywhere else, so that'll affect Anby's ability to apply Shock.
Impact increases how much daze you deal and therefore how quickly you can stun enemies, while electric damage bonus is a pretty self-explanatory stat for an electric character.
For random stats, you'll want attack, anomaly proficiency, and energy regen. This should ensure Anby hits hard, deals decent damage when she does apply Shock, and gets her EX special attack back quickly so she can deal big chunks of daze to enemies. You could try and build Anby towards crits, but since her core skill enhancement, base stats, and Drive Discs won't be helping there, I'd recommend sticking with the three above to maximise stuns. Leave crits to your attack character.
Here's what you'll need to level up Anby in Zenless Zone Zero:
You can get Stun Certification Seals through the Combat Simulation activity that unlocks via the main story. You'll want to select Agent Promotion and then Stun Drill for Anby. Investigator Logs also come from the same place, you just need to choose Basic Material and then Investigation Specialization instead.
As with previous miHoYo games, you'll need to raise your Inter-Knot reputation in order to unlock higher character levels. Once you progress, you'll also be able to customise what enemies you fight in Combat Simulation for your ideal set of material rewards.