Zenless Zone Zero's The Mystery of Arpeggio Fault Event is an HDD Exploration Event inside the Hollow Zero. See how to play the Arpeggio Event in ZZZ, how to unlock it, stages and all the rewards in this Zenless Zone Zero (ZZZ) guide!

The Mystery of Arpeggio Fault Event
Fault Surface		Old Observatory		Outpost Beacon
Laboratory Ruins		Turbulent Corridor		Bangboo Password
Slumbering Land Quest			Where the Mystery Went Quest

The Mystery of Arpeggio Fault Event Information

The Mystery of Arpeggio Fault Event Details

Event Start	November 6, 2024
Event End	December 17, 2024
Unlock Conditions	Clear “Qualification Assessment: Edge” in Hollow Zero
Rewards	+ Knightboo

The Mystery of Arpeggio Fault is a roguelike gameplay mode in Hollow Zero, where Proxies can go through 5 stages of HDD Exploration Commissions in exchange for rewards and Knightboo!

All Events and Schedule

How to Unlock The Mystery of Arpeggio Fault

Mystery of Arpeggio Fault Requirements

In order to unlock the Mystery of Arpeggio Fault event, Proxies must first clear the Qualification Assessment: Edge stage of Hollow Zero. After completing the requirements, Proxies can take on the challenge at Scott Outpost.

Qualification Assessment Guide

The Mystery of Arpeggio Fault Stages

All Areas in The Mystery of Arpeggio Fault

Stages	Unlock
Stage 1: Fault Surface	Progress through the commission The Mystery of Arpeggio Fault - Special Investigation.
Stage 2: Old Observatory	Complete commission The Mystery of Arpeggio Fault - Special Investigation.
	Finish exploring Fault Surface - Fault Floor
Stage 3: Outpost Beacon	Complete commission The Mystery of Arpeggio Fault - Unravelling.
	Finish exploring Old Observatory - Fault Floor
Stage 4: Laboratory Ruins	Complete commission The Mystery of Arpeggio Fault - Final Puzzle Piece.
	Finish exploring Outpost Beacon - Fault Floor
Stage 5: Turbulent Corridor	Finish exploring Laboratory Ruins - Fault Floor

The Mystery of Arpeggio Fault is divided into 5 parts, each can be unlocked after completing certain commissions and different event stages prior.

How to Play The Mystery of Arpeggio Fault

The Mystery of Arpeggio Fault Guide

1. Explore Through the HDD
2. Bump Into Enemies to Defeat Them
3. Upgrade The Tech Tree
4. Select a Data File Before Exploring

Explore Through the HDD

Explore through 5 chapters of a brand new HDD in Hollow Zero. Deep dive into the different areas to look for items and complete your objectives.

Bump Into Enemies to Defeat Them

Bump Into Enemies to Defeat Them
Compare ATK and HP	Enemy Defeated

Bump into enemies to defeat them in exhcange for rewards and EXP. It is recommended to increase your ATK so you do not receive damage when the enemy's HP is less than or equal to your ATK.

Thus, always keep an eye on your HP and ATK before bumping into an enemy!

Upgrade The Tech Tree

Use the Crimson Silk obtained from HDD exploration to upgrade the Tech Tree to enhance your skills, damage, and many more to make your experience more fun in the HDD.

As you progress through the event, you'll receive more Tech Tree nodes and Crimson Silk to customize your loadout and power up even more!

Select a Data File Before Exploring

Select a Data File before exploring to augment your play style inside the HDD. These Data Files provide various buffs, items, and more as you level up.

Like Tech Tree Nodes, you unlock Data Files one after another as you progress through each area.

The Mystery of Arpeggio Fault Agents

All Mystery of Arpeggio Fault Companions

Agent	Stats and Effects
Anby	ATK: 8, HP:25 Cost: 0 Anby has a 20% Crit Rate, dealing double DMG upon a critical hit.
Anton	ATK: 10 HP: 28 Cost: 50 Anton will keep attacking even after his HP drops to 0, each attack thereafter will cause him to lose 1 ATK.
Ben	ATK: 2 HP: 80 Cost: 25 When Koleda is on-field, Ben has a 50% chance to generate an explosive bomb when attacking.
Billy	ATK: 30 HP: 10 Cost: 40 After the Protagonist takes DMG for the first time, Billy's ATK -15. Billy's attack range is 3.
Caesar	ATK: 3 HP: 35 Cost: 30 Caesar has a 50% chance to reflect DMG when hit (taking no DMG and returning the DMG to the enemy).
Corin	ATK: 20 HP: 10 Cost: 20 When Corin gains ATK, she'll gain +1 additional ATK.
Koleda	ATK: 10 HP: 12 Cost: 25 When Ben is on-field, Koleda's attacks are guaranteed to be critical hits.
Lighter	ATK: 5 HP: 40 Cost: 50 Lighter's ATK +20 while the Protagonist has less than 20 HP.
Nekomata	ATK: 12 HP: 15 Cost: 10 Nekomata generates 100 Gear Coins when attacking.
Nicole	ATK: 0 HP: 24 Cost: 20 Nicole's ATK equals 1/100 of the Coin count.
Soldier 11	ATK: 30 HP: 60 Cost: 60 Soldier 11's ATK will not increase.
Yanagi	ATK: 5 HP: 22 Cost: 70 Enemies hit by Tsukishiro Yanagi will create a box, making it so only Yanagi can attack that enemy, and providing EXP equivalent of defeating that enemy everytime she attacks it.

Agents can accompany you as you explore the event's stages. You can unlock agents and increase the amount of agent companions through Contribution Points, which you receive by defeating enemies!

The Mystery of Arpeggio Fault Event Rewards

Get the Exclusive Bangboo: Knightboo

Requirements	Rewards
Complete the exploration of fault Area 1	Knightboo x1
Complete the exploration of fault Areas 2 - 5	Knightboo Core x4

Completing the exploration of fault Area 1 will reward you with the event exclusive Bangboo, Knightboo!

You can also get its copies, the Knightboo Core, by exploring fault Areas 2 - 5. As of now, these are the only way to get copies of Knightboo.

Knightboo Bangboo Guide

All Mystery of Arpeggio Fault Rewards

All Event Rewards
Polychrome	Specialized Shock Chip	Senior Investigator Log
Bangboo System Widget	Official Investigator Log	W-Engine Power Supply
Inter-Knot Credit	Denny

Total Rewards For Every Category

Category	Rewards
Fault Surface	Polychrome x110 Senior Investigator Log x2 Specialized Shock Chip x4 Denny x30,000
Old Observatory	Polychrome x110 Senior Investigator Log x2 Specialized Shock Chip x4 Denny x30,000
Outpost Beacon	Polychrome x110 Senior Investigator Log x2 Specialized Shock Chip x4 Denny x30,000
Laboratory Ruins	Polychrome x110 Senior Investigator Log x2 Specialized Shock Chip x4 Denny x30,000
Turbulent Corridor	Polychrome x110 Senior Investigator Log x2 Specialized Shock Chip x4 Denny x30,000

Battle Pass Rewards

Requirements	Rewards
Clear all stages in the Fault Surface region in "The Mystery of Arpeggio Fault"	x1600
Clear all stages in the Outpost Beacon region in "The Mystery of Arpeggio Fault"	x1600

Clearing all the stages in the Fault Surface and Outpost Beacon reagions in "The Mystery of Arpeggio Fault will reward you with a total of 3200 New Eridu City Fund EXP.

Note that you can claim this reward on the New Eridu City Fund menu and not on the event's menu.

New Eridu City Fund Battle Pass Guide

Zenless Zone Zero Related Guides

All Events and Schedule

Ongoing Events

Event Guide	Event Duration
Little Knight's Big Charge	04/09/2025 - 04/21/2025
En-Nah Into Your Lap	04/02/2025 - 04/22/2025
The Final Callback	04/02/2025 - 04/22/2025
Virtual World: Battle Storm	04/02/2025 - 04/14/2025
All-New Program	03/12/2025 - 04/22/2025
TV Schedule	03/12/2025 - 04/21/2025
March On, Tiny Titan!	03/12/2025 - 04/21/2025

Past Events

Event Guide	Event Duration
141 Exclusive Bazaar	08/02/2024 - 08/12/2024
141 Friendship Fair	10/27/2024 - 11/04/2024
141 Going Green for Everyone	02/26/2025 - 03/10/2025
A Dream Come True at Last	01/24/2025 - 02/05/2025
Advanced Bounty - Routine Cleanup	03/26/2025 - 03/31/2025
Bangboo vs Ethereal	12/20/2024 - 01/20/2025
Before the Curtain Rises	01/13/2025 - 01/29/2025
Best Wishes, Miyabi	12/12/2024 - 01/03/2025
Brilliant Overture	01/22/2025 - 03/11/2025
Camelia Golden Week	08/21/2024 - 09/23/2024
Click Click Hollow Reporter	02/02/2025 - 02/17/2025
Coffee Sorcery: Combat Simulation	09/04/2024 - 09/09/2024
Coffee Sorcery: Tuning	09/18/2024 - 09/23/2024
Collab Designer	01/09/2025 - 01/20/2025
Combat Footage Review	01/03/2025 - 01/13/2025
Cunning Generosity	07/04/2024 - 08/13/2024
Daily Life of a Pubsec Officer Event	08/30/2024 - 09/09/2024
Delivery Cat Woes	03/16/2025 - 03/31/2025
DIY Bangboo Fan Art Contest	07/15/2024 - 07/28/2024
Don't Get Greedy	07/19/2024 - 07/26/2024

Permanent Events

Event Guide	How To Unlock/Rewards
Road to Proxy Greatness	Reach Inter-Knot Level 8. Master Tapes Boopons Polychromes
Rookie on the Road	Reach Inter-Knot Level 8. Demara Battery Mark II Starlight Engine Bagboo Slice of Time Ben

All Web Events

List of Web Events