The Hollow Deep Dive System is the Rogue-like gameplay aspect of Zenless Zone Zero (ZZZ). See the Hollow Exploration explained, all the hollow event tiles, and information on the hollows here!

Hollow Deep Dive System Explained

What is the Hollow Deep Dive System

The Hollow Deep Dive (HDD) System is a feature that proxies use to tread inside the Hollow. In the system, you can synchronise with your Bangboo assistant, Eous.

You need to use Eous to explore Hollows which takes the form of a Hollow Visualization TV Wall or Board. As the name suggests, it is a form of a board made up of TVs.

All HDD System Features

Hollow Deep Dive System Visual Elements

• Part 1: Main Stage Objectives
• Part 2: More Instructions in the Pop-Up Messages
• Part 3: Tread through the TV Wall
• Part 4: Avoid Hollow Pressure
• Part 5: Corruption Buffs Enemies
• Part 6.1: Collect Observation Data
• Part 6.2: Collect Items in the Hollows
• Part 7: Use Bangboo Pug-Ins
• Part 8: Get and Use Resonium

Follow the Objectives

On the HDD System Screen, the upper left corner is where the objectives are. This is where the stage's main objectives are. These are also shown in the menu before entering the stage.

How Pop-Up Messages Work

As you progress through the stage, messages on the upper right corner will flash for a few moments to instruct you on what to do or perhaps have dialogues just included within the story whenever you trigger anything in the stage.

Traversing the TV Wall

The light grey image of the bangboo is Eous. It's the bangboo you're consciousness has been synced to. It seems you can move Eous to navigate through the TV wallboard!

Avoid Increasing Hollow Pressure

Pressure is the meter in which you gain corruption inside the Hollow. In the middle above the characters. The more pressure you gain the more likely you'll get corrupted.

Checking the Hollow Ether Activity on the HDD commission screen will determine whether the accumulation of corruption will be fast or not.

When the meter on pointed on the lower left side, it has low activity. If it's in the middle, it's a medium Ether activity. If the meter is on the lower right side, there's a high ether activity.

How to Lessen Pressure

To lessen pressure, you must get to a safety zone to reduce your pressure. Take note that once out, taking actions such as engaging in battle and obtaining inventory materials will slightly increase your pressure.

It's better to keep an eye on the meter and plan out your route to avoid being corrupted!

Hollow Corruption Debuffs

Once the pressure reaches 100, the squad members will gain one random corruption and the pressure will reset to zero. Corruptions seems to be debuffs for your allies which would make the stage harder.

There are five slots for corruption once that is filled up when you accumulate the pressure inside the hollow, the squad's HP will drain this time. Once all HP from the team has been drained, the mission will be terminated.

Collect Observation Data in Hollows

Observation Data is something you can collect inside the HDD stage. It acts as a symbol of accomplishment so you can gain more rewards. Each stage has three of them and if you get three in each stage, that will raise the rating of the commission!

Collect Inventory Items

There are many things you can collect as an inventory item within the hollow stage. You can collect Gear Coins to use to open certain pathways. You can collect Dennies which is the common currency used in almost everything within the game.

You can also get Gold Resource Crates that are like Treasure Chests.

Use Bangboo Plug-Ins

Off on the lower left side of the screen, is the bangboo plug-in. These are usable gadgets within the hollow stage. You can tap it to check its effects or you can hold it and use it instantly.

Use Resonia for Buffs

Resonia are Etheric Matter that can only be found within the hollow stage. Resonium or Resonia can buff your squad to gain an edge in exploration or combat!

All Zenless Zone Zero Hollow Events

All Hollow Environments

Event	Description
Unstable Area	An area that requires a slow and careful approach, demanding step-by-step exploration. You can come this far, but no further.
Unknown Area	An uncharted area. A survivor’s nightmare; a desperate battle to the death; the nemesis of all investigators; and “master”of the Hollow.
Secret Path	Enter a hidden area. A secret is only as valuable as the price it takes to get it.
Sturdy Obstacle	An obstacle that blocks the path. Be it a towering wall or charred ruins. Regardless, this path is blocked.
Fragile Obstacle	The remnants of the obstacles still obstruct the path. With a little push, they can be overcome.
Broken Obstacle	An obstacle that can be smashed. Break it a few times to pass. Make sure to have at least one Agent in the exploration team is wearing a hard hat properly. Or if your Bangboo happen to have a sturdy shell, that should also be fine.
Mists	A safe teleporter The twisted Ether outlines a twisted road. At least it doesn’t look dangerous.
Fissure Leading Deeper	A fissure to the depths of the Hollow. Once you step into it, there’s no coming back. This seemingly friendly elevator attendant will help you proceed downward, but if you need to return... you’ll have to figure out another way.
Fissure Leading Outside	A fissure to an upper floor of the Hollow. Once you step into it, there’s no coming back. This seemingly friendly elevator attendant will help you proceed upward, but if you need to return... you’ll have to figure out another way.
Downward Passage	A portal to the depths of the Hollow. You can return to it at any time. This understanding elevator attendant will help you proceed downward. If you need to return, this attendant is always ready to serve.
Upward Passage	A portal to the previosu floor. You can return to it at any time. This understanding elevator attendant will help you proceed upward. If you need to return, this attendant is always ready to serve.
Teleporter	A portal to a designated area. A path so secret not even Proxies know its destination. As for where it goes, you will know it when you are there.
Surprise Box Area	Enter the portal to a random space. What awaits remains a mystery. You have to step into the unknown to unveil the answer.
No Loitering Zone	The way out of the current special area. Whatever events unfolded in the Hollow are coming to an end.

All Hollow Devices

Event	Description
Observations	Observe the location of the next route. The map drawn by the data isn’t all there is, and you may be able to discover new things by observing in person.
Trigger Switch	A trigger switch that activates mechanisms or equipment. Once triggered, it cannot be undone, just like there is no turning back on your fated path.
Button Switch	A button switch only works while held down. Once released, its utilization will fade away, just like time and tide wait for no man.
Control Lever	A control lever that activates mechanisms or equipment. Bad news: Operating it violates safety regulations. Good news: The safety supervisor has been tossed into a Hollow.
Steering Device	A button that changes the orientation of the mechanism. An intricately designed device. The gears at the bottom are solely for decoration.
Reset Button	A button switch that resets all mechanisms in a specific area. Finally, a fix to your past mistakes in unlimited supply.
Lever	A switch that allows repeated adjustment of the controlled mechanism or equipment. This switch underwent rigorous quality control, at your disposal for trial and error without any risk of wear and tear. There’s no guarantee, however, that the Ethereals won’t suddenly join your fun.
Tracks	A tool that allows you to switfly move to the end of the track. Sometimes, it’s a much-needed boost. Other times, it could be a pesky obstacle.
Closed Gate - Wealth	A closed gate that only unlocks after you pay enough Gear Coins. Money makes the world go round. Or coins if you’re a Bangboo.
Closed Gate - Puzzle	A closed gate that will only unlock after you activate a mechanism. Residents in New Eridu are used to 24/7 locksmith services... but in the Hollows, one has to figure it out on their own.
Closed Gate - Corruption	A closed gate. Forcefully opening it will either increase or reduce Corruptions. Once a pathway for assessing Corruption risks, this place is now abandoned and giving off an eerie aura... Should we take the risks and pass through?
Eject	Eject in a specified direction. Efficiency is key for Hollow Raiders, even if it means sacrificing the safety brought by a seat belt.
Closed Gate - Challenge	A locked gate that only unlocks if you have performed well in your last battle. The residual Ether will corrupt its fragile locking core, so be sure to clean up on the battlefield.
Opened Gate	The closed gate has now opened. Will it be what you’ve been longing for hidden behind it?

All Hollow Resources

Event	Description
Assets	Obtain Dennies. Nobody takes Dennies into a Hollow. These shiny coins represent the legacy of a civilization in demise.
Gear Coin Case	Obtain a large amount of Gear Coins. Encounters with them can instantly make you the richest person in the Hollow.
Performance Evaluation Point	Earn Z-Merits. Among investigators, there’s a lot of insider lingo, and “you can earn Z-Merits” is the most unique one. It could be a joke on rookies, a threat to juniors, admiration for seniors, or a curse on troublemakers... Because there’s only one way to earn Z-Merits — participating in the investigation of Hollow Zero...
Swift Supply	Obtain a random item. Activate a Retriever Bangboo and see what it brings back.
Obtain Plug-In	Enhance Bangboo plug-ins. The thirst for power is driven by paranoia.
Gacha	Get a Resonium. You can never be its permanent master - but it makes for a good short-term ally.
Corrupted Gacha	Grants you an Artifice Resonium. Even through the galss, you can see the unstable Ether energy coursing near the Resonium... but you want to give it a try, right?
Resonium Catalyst	Catalyzes the Resonium in your inventory. The chaotic Ether has been subdued and incorporated into the Resonium for your use, but in pursuit of greater power... you decide to unleash it.
Bangboo Merchant	Can be traded with Bangboo merchants. They carry wares and love to trade. They’re crazy about Gear Coins - they’re Bangboo merchants!
Safety Zones	A safety zone that can reduce your Pressure. Danger and evil are completely quarantined. All you need is time to calm down.
Rest Areas	A rest area to recover HP. Even if the mind is willing, the body may need rest.
Disconnection	Increases Pressure. The voices of surrounding companions suddenly disappear, leaving you all alone.
Corruption	Lose HP. You know it’s grievously harmful to the body, but you can’t stop yourself from breathing.
Purification Room	A purification room that can remove Corruption. The small wings on the purifying device provide a sense of relief, despite lacking any magical power.
Ether Dewdrops	A rest area where incapacitated Agents are revitalized. The Hollow grants vitality, as if out of compassion.
Observation Site	Hollow Observation Data. The very soil and nutrients for cultivating a Carrot.
Deserted Observation Site	Gathered Hollow Observation Data. It’s been taken by someone. They even took the storage disk.
Elite Investigator's Supply Box	A chest holding the most advanced Agent upgrade materials. A testament to the remarkable adventures of a legendary investigator.
Senior Investigator's Supply Box	A container holding advanced Agent upgrade materials. A smart mind is an investigator’s most powerful weapon, and the materials in this chest provide efficient ways to use this weapon.
Opened Supply Box	A chest that has been opened. It contains nothing but Ether-tainted air.

All Hollow Threats

Event	Description
Crisis	Battle against a normal enemy. Every adventurer comes across this type of enemy, who is meager in strength but vast in number.
Peril	Battle against a tough enemy. Not necessarily the most difficult of enemies, but you’ll pay the price for underestimating them.
Impasse	Battle against the Hollow’s toughest enemy. A survivor’s nightmare; a desperate battle to the death; the nemesis of all investigators; and “master” of the Hollow.
Doube Crises	Fight two elite enemies at once. Two fists against four hands.
Timed Battle	A special battle that must be completed within a time limit. Boldly, greedily, marching towards annihilation.
Gatekeeper	Defeat the enemy to venture deeper into the Hollow. These foes are ruthless monsters but also loyal guardians.
Final Battle	Battle against the final enemy. The guy you hate seeing the most is at the place you need to get to the most.

All Hollow Visitors

Event	Description
Normal Enemy	Wandering enemies with low threat level. These small-time minions often serve as the inital trial for adventurers.
Elite Enemy	Wandering enemies with a high level threat. A cornerstone for skilled Investigators, and sometimes a stumbling block for the careless.
Boss Enemy	The most formidable foe within the Hollow, patroling its territory. Nightmares encroach, and hope is nowhere to be seen.
Bomber	An enemy carrying dangerous explosives A dangerous person and explosives - the perfect partner.
Companions	A friendly unit. They go where you go, following your lead.
Golden Bangboo	Defeat it to gain a large amount of Gear Coins. For the merchant association, these rogue Bangboo have caused great losses, but for Hollow Raiders, they are precious treasures.
Dead End Butcher	A terrifying enemy. A butcher roaming through a dead-end, waiting for lost souls.
Friday	An intelligent construction machine. Despite appearing excessively over-the-top to others, this pile driver exemplifies an unwavering commitment to fulfilling its mission.
Hans	An intelligent construction machine. A heavy-duty grappler with a soul of a hot-blooded man pursuing his dreams with heroic fervor.
Greta	An intelligent construction machine. This boring machine is a young girl who guards her beloved with undying passion.
Train	A train. It speeds by, not a common sight in the Hollows.
Obstacle	An obstacle that can be pushed aside. Probably the most flexible and least irritating among all the annoying obstacles in the Hollows.
Moveable Obstacle	An obstacle that can be pushed aside. It switches places with the Bangboo when pushed against a wall. It’s much heaver than it looks, and without the help of wheels, you can’t move it.
Bomb	A bomb used to destroy barriers. KA-BOOM!

All Hollow Encounters

Event	Description
The Opportunist	He’s really pushing that “buy now, pay later” deal. If we think we can handle the interest, maybe it’s worth a shot...
Masked Scholar	The Masked Scholar is carrying his homemade semi-fini-er, no, test subject! Maybe it’ll be useful?
Investigator	They are executors of the Association’s will, and pioneers of the Hollows, who might serve as temporary allies. Their positions, identities, and titles may differ... but aside from that, you are all alike.
Hollow Raider	They are peers and competitors. While most Hollow Raiders are friendly enough, it doesn’t always pay off to trust them too much.
The Truth	The Hollows are where the truth goes to die. No journalists can survive here, and any secrets disappear into the Ether.
Passage	On the steps there... is that personal property left behind by some passers-by, or a trap laid by someone blocking the way? If you’re feeling brave enough, go on and take a look!
The Behemoth	This peerless steel beast lies wrecked in the Hollows, no longer able to roar. But its story is not over, as to this day, strange guests still traverse its chassis.
Gold Excavation Point	One can hardly imagine how many Dennies are buried in the depths of the Hollows. If you’re eager enough... why not try your luck?
HSO Task Force	A Task Force from Hollow Special Operations, an elite operations unit affiliated with H.A.N.D. These elite individuals are characterized by their composed demeanor, distinct from that of ordinary investigators.
Distress Signal	A distress signal from an unmarked area. Is it a plea for help from injured survivors, or is it a sinister trap? Proceed cautiously to uncover the truth.
Resource Recycling Squad	An outsorced H.I.A. Investigation team. They are not wearing uniforms, which makes it hard to distinguish which members are real investigators and which ones are actually licensed Hollow Raiders...
Dilapidated House	A dilapidated house in the old capital Despite its crumbling structure, there may be something useful to find within... as long as it still holds together...
Paid Rest Area	A modified commercial rest stop with a coin machine at the entrance saying “paid service,” a typical style of the TOPS merchants.
White Star Institute Research Station	A small research station belonging to the White Star Institute, guarded by several special agents and Handlers.
Defense Force Logistics Hub	A small logistics site belonging to the New Eridu Defense Force, garrisoned by fully armed soldiers equipped with military vehicles.

What are Hollows?

An Apocalyptic Level Disaster

Hollows are apocalyptic-level disasters that plague the world of Zenless Zone Zero. These disasters are in the form of abnormal spherical dimensions and will corrupt everything they touch.

Entering a hollow is extremely dangerous as one could likely get corrupted and mutate to become an Etherial. Etherials will attack anything that's not like their kind.

Profit From Materials in Hollows

There are mysterious materials like Ether within the hollows that companies like the Belobog Heavy Industries want. That is also why Proxies and Agents venture inside it!

Belobog Heavy Industries Faction Guide

Depicted as TV Tiles in the HDD System

The pathways in the hollows are shown as TV Tiles within the Hollow Deep Dive System to lessen the effects of the corruption. There, proxies must move their bangboo to help navigate the area to accomplish goals and defeat enemies with the agents!

Zenless Zone Zero Related Guides

Zenless Zone Zero Wiki Front

Guides by Category

Zenless Zone Zero Categories
News and Game Info	Redeem Codes
Characters	Tier Lists
W-Engine	Drive Discs
Signal Search	Bangboo
Events	Travel
Shops	VR Device
Enemies	Bosses
Hollow Zero	Shiyu Defense
Rally Commissions	Arcade (Godfinger)
Items	Commissions
Mewmew Medals	Trust Events

Zenless Zone Zero Tips and Tricks

Gameplay Guides
How to Level Up Characters	How to Build and Enhance Characters
How to Ascend (Promote) Characters	How to Recover Battery Charge
How to Raise Your Inter-Knot Level	All Inter-Knot Level Rewards
Daily and Weekly Server Reset Times	How to Change the Time
List of All Achievements	Trophy Guide
Missing Mini Cargo Truck Locations and Rewards	Reroll Guide
Microtransactions and Best In-App Purchases	How to Increase Agent Trust Level
Fast Travel Guide: How to Teleport	How to Modify and Upgrade W-Engines
How to Gain Energy	How to Heal Characters
Compendium Guide	List of Primer Trials and All Rewards
Best Standard Banner Character Guide	How to Get Promoters for Random Play
Exploration Elements	Workbench Guide
How to Level Up Drive Discs	How to Upgrade Core Skills
How to Pet Cats	Public Telephone Guide
How to Change Your Name	All Stats Explained
How to Raise Your Proxy Rank	Immersive Storytelling Mode Guide
How to Get and Change Namecards	Skill Enhancement Guide
How to Take Pictures	How to Level Up and Ascend Bangboos
Best Battery Priority Guide	Best A-Rank W-Engine to Get from the Bundle
Combat Guides
Basic Combat Guide	How to Daze and Stun
Chain Attack Guide	Ultimate and Decibel Rating
Perfect Dodge and Counter	Perfect Assists and Parries
Attribute Anomaly	What are Additional Skills?
How to Destroy Enemy Parts	How to Do EX Special Attacks
How Do Shields Work?	-
Items and Collectibles
How to Farm Polychromes	How to Get and Use Residual Signal
How to Get and Use Fading Signal	How to Get and Use Encrypted Master Tape
Best Ways to Farm Denny (Money)	How to Get and Use HIA Commemorative Coin
How to Get and Use W-Engine Chip	How to Get and Use Ether Battery
How to Get and Use Boopon	How to Get and Use Bangbuck
How to Get and Use Monochrome	Exclusive Skins for W-Engines
How to Get Dynamic Wallpapers	How to Collect Observation Data
How to Use Photowall	How to Get Cat Food Cans
HIA Coins Sixth Street Locations	HIA Coins Brant Street Locations
HIA Coins Lumina Square Locations	HIA Coins Ballet Twins Road Locations
Game Modes and Dailies
Dailies - Errands Guide	Hollow Deep Dive Explained
Officer Mewmew Medal Locations and Challenges	Notorious Hunt Guide
Routine Cleanup Guide	Casual vs Challenge Mode
Frequently Asked Questions
Should You Choose Belle or Wise?	Does Zenless Zone Zero Have Crossplay?
Are There Multiplayer Features?	How to Transfer Data
How to Exit the Game	How to Play With Controller on PC/Mobile
Birthday Guide: What Do You Get On Your Birthday	Which Server Should I Use?
New Eridu City Fund Battle Pass Guide	Can You Reset an Account?