Skip to content
Zenless Zone Zero Wiki

“On air, on time — New Eridu never sleeps.”

Explore →

Back to School

Last updated 2026-02-02

Back to School is a Story Commission and part of Koleda Belobog's Agent Story: Schoolyard Powerhouse. It is unlocked during Schoolyard Powerhouse (II).

Steps

  1. Investigate the Hollow
  2. Eliminate obstacles and venture deeper into the Hollow
  3. Collect all the verification devices
  4. Open the gate and investigate the anomaly
  5. Assist Koleda and stop the principal

Enemy Info

May also appear

Gameplay Notes

Trial Mode

Inter-Knot Rank: 

Elite Proxy Elite Proxy

Team
Position
Agent
& W-Engine
Skills & Equipment Stats

1


Icon Basic Attack Basic Attack Lv. 8
Icon Dodge Dodge Lv. 8
Icon Assist Attack Assist Lv. 8
Icon Special Attack Special Attack Lv. 8
Icon Chain Attack Chain Attack Lv. 8
Icon Core Skill Core Skill Lv. 5

Icon Stat HP HP: 10,339
Icon Stat ATK ATK: 1,725
Icon Stat DEF DEF: 699
Icon Stat Impact Impact: 168
Icon Stat CRIT Rate CRIT Rate: 33.8%
Icon Stat CRIT DMG CRIT DMG: 54.8%
Icon Stat Anomaly Mastery Anomaly Mastery: 97
Icon Stat Anomaly Proficiency Anomaly Proficiency: 96
Icon Stat PEN Ratio PEN Ratio: 0%
Icon Stat PEN PEN: 0
Icon Stat Energy Regen Energy Regen: 1.2
Icon Stat Energy Generation Rate Energy Generation Rate: 0%
Icon Stat Energy Limit Energy Limit: 120
Icon Fire DMG Bonus: 21%

King of the SummitKing of the SummitKing of the SummitKing of the SummitShockstar DiscoShockstar Disco
Drive Disc Lv. 9
Set Bonus
Shockstar Disco 2-Piece
King of the Summit 4-Piece

Dialogue

(Upon starting the commission)
Koleda: This can't be the entire Hollow! Let's keep going and explore further.
(Interact with the Observations tile)
Koleda: Is this... a railroad switch? Weird, it looks like a mining one...
(Koleda activates the switch)
Koleda: Seems like we're going in the right direction!
(She approaches an obstacle)
Koleda: Let's give it... a gentle hammering...
(She approaches a sturdy wall)
Koleda: Hyaa!!
Koleda: This wall is tough...
Koleda: But my hammer is harder! Again!
Koleda: Ha! Hmph.
Koleda: There's the path. Follow me, Proxy.
(Interact with Koleda)

Lost in Hollow

The following is recorded in the Video Archive
Story "Lost in Hollow"

Video Summary: New Eridu's future... is accompanied by dangerous Hollows.
Story Description: Why didn't the principal take care of the Hollow despite knowing it was dangerous? You went into the Hollow to see what was going on.


Koleda: I've never liked that principal.
Koleda: Obviously, he's super suspicious. I mean, what principal would just leave a Hollow to grow all willynilly next to his school? And even try to cover it up?
Koleda: But, it's not just because of that.
Koleda: I... I'm not great at dealing with adults who are so... adult-like. I never get what they're thinking.
Koleda: They barely ever say what they're really thinking. Maybe they'll spill to their friends, but to their family? Yeah, never.
Icon Dialogue Talk Did it remind you of your father?
(ProtagonistProtagonist): (‍Is this bringing up memories of your father?Is this bringing up memories of your father? / Does this make you think of your father?Does this make you think of your father?‍)
Koleda: Hah? No way!
Koleda: ...Now's not the time for chitchat though. Let's go, Proxy. If you need my hammer, just say the word.
(After the cutscene)
Fairy: I have detected unusual activities in a certain area.
(SiblingSibling): That must be the real entrance to the Hollow.
Koleda: Lead the way, Proxy. If you need me to smash some walls, just say the word!
(Obtain (Hollow) Koleda's Demolition Hammer (Hollow) Koleda's Demolition Hammer)
(Bump into a sturdy wall)
Koleda: Hey, it's starting to loosen! Let's give it another try!
(Interact with a sleeping enemy for the first time, optional)
Koleda: This Ethereal is still inactive!
Koleda: Just like this...
Koleda: Done!
(Interact with another sleeping enemy, optional)
Koleda: Hammered flat!
(Approach the switch)
Koleda: Looks like it could open a path for us. Touch it, Proxy!
(Interact with the enemy blocking the path)
Fairy Smart Intervention: "A group of active Ethereals is blocking the way."
Fairy Smart Intervention: "You can either eliminate them and proceed or retreat and explore this area further."
Activated Ethereals: A small group of Ethereals, but they seem very active. They look even livelier than a bunch of elementary school kids when they're supposed to be asleep. Must be living the good life~
Master, I reckon fighting is now about [sic] best choice.
Danger
Eliminate them!

(Head to the next area)
Koleda: *cough* Watch out for that pit, Proxy!

Careful Action

The following is recorded in the Video Archive
Story "Carefully"

Video Summary: When the clouds of suspicion linger, it's not advisable to rush ahead.
Story Description: The Hollow is filled with mines and dust. Koleda suggests avoiding unnecessary engagements to avoid disturbing the Etheric environment.


Koleda: The Ethereals here aren't very big. Seems like the Ether concentration isn't too high...
Koleda: However, the environment is highly unstable, meaning that it's often disturbed...
Icon Dialogue Talk There's a lot of mines...
(ProtagonistProtagonist): There sure were a lot of Ether crystal mines just now...
Icon Dialogue Talk The air is full of dust.
(ProtagonistProtagonist): The air is full of dust from mining Ether crystals...
Koleda: That's right. All this points to one conclusion: someone has been illegally mining Ether resources here.
Koleda: Hmph. How much you wanna bet all this dust in the air is just like that "chalk" on the principal's clothes just now?
Icon Dialogue Talk Unsurprising...
(ProtagonistProtagonist): (‍Yeah, it seemsYeah, it seems / Unsurprisingly,Unsurprisingly,‍) the principal must have something to do with what's happening here.
Koleda: Aaah damn it! He's turned this Hollow into a ticking time bomb! And right next to the school, too!
Koleda: This Hollow is extremely unstable. It could rapidly expand at any moment... Proxy, can I ask you a favor?
Koleda: From here on out, please do whatever you can to avoid fighting. It'll just disturb the Ether environment even further. I'm worried something's gonna happen.
Icon Dialogue Talk Leave it to me.
(ProtagonistProtagonist): (‍I understand. Just leave it to me.I understand. Just leave it to me. / I got it. Leave it to me!I got it. Leave it to me!‍)
Koleda: Thanks. I'm counting on you.
(After the cutscene)
Koleda: Let's continue, but be careful!
(Press the button)
Fairy: I have marked a suspicious location for you, Master.
Fairy: I am unable to assess the threat level nearby due to the sealed gate.
Fairy: I have located the verification devices needed.
(SiblingSibling): (‍Wise, can you get through?Wise, can you get through? / How are we supposed to get through? Let's keep exploring and see.How are we supposed to get through? Let's keep exploring and see.‍)
(Attempt to open the gate, optional)
Fairy: Not all verification devices have been found.
(Pick up a verification device)
Koleda: This little gadget's a bit complicated, isn't it, Proxy?
(Unlock the path to the northern device)
Fairy: We are getting closer to one of the verification devices, Master.
(Bump into a bomb for the first time, optional)
Koleda: Careful! There might be explosives here.
(Bump into a bomb again, optional)
Koleda: Let's come up with another plan.
(Bump into a bomb 5 times in a row — one of the following will play, optional)
Koleda: Calm down, Proxy. We don't want a mining accident...
Koleda: Can we find another way around?
(Interact with the enemy blocking the device)
Fairy Smart Intervention: "It appears the Ethereals here will not let us pass easily."
Fairy Smart Intervention: "It appears a battle is inevitable."
Activated Ethereals: The active Ethereals gather, like a group of ten-year-olds crowding around an arcade machine just as you're about to leave without using all the coins you inserted earlier. It's somewhat uncomfortable.
Combat is the most effective way to advance the Hollow exploration.
Danger
Don't hesitate. Eliminate them!
(Pick up the second device)
Koleda: We've got two! Let's look for the last one!
(Destroy the wall to the right of the northern switch)
Fairy: Master, please be careful.
Fairy: The sound of the wall collapsing has attracted Ethereals.
(Interact with the wandering enemy, optional)
Fairy Smart Intervention: "Warning. You are about to be discovered by a wandering group of active Ethereals."
Fairy Smart Intervention: "You can either throw random items to distract them or face them head-on."
Activated Ethereals: A group of active Ethereals is wandering around nearby, doing nothing like kids who get out of school at 2 pm. You're starting to feel a little jealous.
The Ethereals are about to notice us!
Danger
Eliminate them!
Exit
Throw something to distract them and avoid combat
Lose 300 Gear Coins (Success rate: 100%)
(First time)
Fairy Smart Intervention: "Master, there's no need to throw so many Gear Coins. Based on my analysis, you can distract them by throwing 3 or 30 Gear Coins."
Fairy Smart Intervention: "The success rates are 1% and 10% respectively."
(Subsequent times)
Fairy Smart Intervention: "I wish you were this generous when spending Dennies."
Fairy Smart Intervention: "Your actions have managed to distract the Ethereals.[Note 1] Leave now while you can."
Unknown
Throw something to distract them and avoid combat
Lose 30 Gear Coins (Success rate: 10%)
[Note 2]
(If successful)
Fairy Smart Intervention: "'This works too!" Second Assistant exclaims from behind you like an ignorant peon.
Fairy Smart Intervention: "Your actions have managed to distract the Ethereals. Leave now while you can."
(If unsuccessful)
Fairy Smart Intervention: "I am sorry, Master, but I do not think your actions have managed to distract the Ethereals."
Fairy Smart Intervention: "Fortunately, the Ethereals have not noticed your presence either. Will you try again?"
Exit
Step back for now
(Use the teleporter)
Koleda: You trip or somethin'? No wait, it's a secret passage!
(Interact with a Gear Coin gate)
Locked Valve: Explorers often encounter various mechanisms in Hollows.
Take this safety valve for example, it can only be opened once a specific number of Gear Coins have been inserted.
Even if something is taken, the owner can still receive a substantial sum of Gear Coins in return.
Activate Device
Pay the required amount of money
Pay 2500 Gear Coins
Exit
Explore the surrounding area
Do not pay
(After paying the toll)
Fairy: Sufficient Gear Coins paid. Authentication successful. Opening valve.
(Interact with the enemy by the Gear Coin gate, optional)
Fairy Smart Intervention: "Master, I have detected multiple hostiles ahead. They are likely to be gang members. Many of them are armed with low-quality Ether weapons."
Fairy Smart Intervention: "I must remind you that their weapons are prone to triggering Hollow activity reactions. You should avoid combat with them."
Gangsters in [sic] a Break: The gang members are chatting about the weather, their dreams, and their love for their family. Ironically, the inferior weapons in their hands make their enemies worry more about them than their own family members do...
If we have to fight, we can approach them quietly...
Danger
Let's fight, then.
Enter combat
Exit
Avoid them
Go through the door over there?
(If a sleeping Ethereal was nearby after fighting the gangsters)
Fairy: Master, the battle just now stirred up the nearby Ethereals.
(The enemy begins to wander)
(Pick up the third device)
Fairy: Verification completed. The door is open.

(Open the gate)
Koleda: We can finally figure out what's going on here.
(Approach the target)
(SiblingSibling): (‍I'm feeling a bit nervous, Wise...I'm feeling a bit nervous, Wise... / Be careful, Belle.Be careful, Belle.‍)
(Reach the target)
(Gang members surround the group)
Gang Leader: That's it! Someone snuck in!
Gang Leader: Take 'em down, boys!
(Enter combat)
Koleda: An ambush? Don't panic. Keep the proxy safe!
(Defeat the first wave of enemies)
Bangboo (Wise / Belle)Bangboo (Wise / Belle): (‍Keep this going and we'll be out soon!Keep this going and we'll be out soon! / That's it! Break through!That's it! Break through!‍)
(Approach Elton)
Koleda: Is that... the president? When did he get back?
(Idle)
Elton: What a pain...
(Talk to Elton)

Perpetrator

The following is recorded in the Video Archive
Story "Perpetrator"

Video Summary: It's not uncommon to see someone proud of their ability to navigate the gray areas.
Story Description: It turns out the principal is the one behind all this. His collusion with a gang for profit through mining and utter neglect for the children's safety provoked Koleda's fury.


Principal Elton: If it isn't the president of Belobog Industries, Ms. Belobog. It has been a while. Or should I call you...
Principal Elton: Our newest transfer student, young Koleda?
Principal Elton: Don't be so surprised. Your name may not be in the register, nor have you ever shown your face to me...
Principal Elton: But as the principal of this school, I have my ways of knowing.
Principal Elton: Though I am a little late to the scene, I realized you were scheming something. It's good I arrived on time.
Principal Elton: President Koleda, are you not busy? No matter how much you enjoy playing house, don't forget that you have more important things to do than interfering with my goldmine.
Koleda: Excuse me, but since I'm already here... does that mean you'd know something about the group of criminals illegally mining Ether resources — making the Hollow more and more unstable?
Principal Elton: What? Is that so... I had no idea.
Koleda: They're right next to you. You gonna stick to that story even if the Association comes?
Principal Elton: Nothing's happened with this Hollow yet, so why would the Association get involved? They have countless more urgent Hollow disasters to deal with every day. Meanwhile, this risk is just that: a risk, and nothing more.
Principal Elton: We can bet Dennies on it. Even if you send the Association the coordinates, all they'll do is call me to confirm its existence. By the time they actually send someone here, my child might already be in university.
Koleda: ...
Principal Elton: Little president. This is the world of grown-ups. The rules of the game are made for mature adults.
Principal Elton: You still have the chance to learn these rules. Do me a favor and, try the mature thing for a change: run along now, go watch a play, cry a bit. Let go of your unnecessary sense of justice, and forget all that happened here.
(After the cutscene)
(Elton and the gangsters walk away)
Elton: By the way, my good friend is looking for a contractor...
Elton: Should I give him a call and mention Belobog Heavy Industries?
Koleda: ...You're really treating me like a kid, huh...
Koleda: ...Who said you could leave just like that?!
(Koleda chases after them and starts a fight)
(SiblingSibling): (‍Wait a sec, Koleda!Wait a sec, Koleda! / Calm down, Koleda...Calm down, Koleda...‍)
(SiblingSibling): This is (‍dangerousdangerous / riskyrisky‍)! Stay close!
(Join the fight)

Sudden Conflict

The following is recorded in the Video Archive
Story "Sudden Conflict"

Video Summary: We're used to the unexpected.
Story Description: Your fearless enemy suddenly attacks, so you have no choice but to fight.


Principal Elton: Oh? Welcome back President Koleda.
Principal Elton: Poor me... I feel like a tired office worker trying to meet their deadlines at a cafe, and there's a crying child that just won't shut up.
Principal Elton: Nothing is just black or white. And in the gray area, I just want to make a little extra dough. That's not against the rules.
Principal Elton: Why do you insist on harassing an aging father, who simply wants to make some extra income — to give his child a better life and education?
Koleda: How do you have the nerve to say that...?!
Koleda: So your kid deserves a better life? She's not the only kid. Have you never once thought of how, if the Hollow expanded, all the other kids in your school would be in danger too?
Principal Elton: It won't. My luck has always been good. You see, sometimes, you simply have to believe in your luck for it to do its job.
Principal Elton: And, on the off chance things don't work out, it wouldn't be my responsibility.
Principal Elton: After all, if you and your people clashed with these thugs in the Hollow, thereby causing an unfortunate disaster... That's not something I can help, right?
Gang Leader: That principal sure is a slippery one. But—
Gang Leader: Listen up, boys! Let's teach these punks a lesson!
Icon Dialogue Talk The Hollow might expand!
(ProtagonistProtagonist): Oh no! If they start a fight now, it'll disturb the Ether environment!
Koleda: These bastards— The hell is wrong with you!
(Enter combat)
Hollow Thug: Ahhhhhhhhh!
Bangboo (Wise / Belle)Bangboo (Wise / Belle): Hollow activity is on the rise!
Koleda: We'll just have to fend them off first!
(After defeating all enemies)

Deliberate Crime

The following is recorded in the Video Archive
Story "Deliberate Crime"

Video Summary: The ability to assess priorities is a form of wisdom.
Story Description: The gang's reckless actions have led to the expansion of the Hollow, and you were separated from the principal. You heard a familiar voice. Has a kid got caught in the Hollow?


Koleda: Don't let the principal get away!
Gang Leader: You lot, stay here and hold them off! Once we get out, each of you are getting a new car! ...Principal, sir, come with me!
Principal Elton: Haah... haah... Wait...
(SiblingSibling): (‍...We've detected that the Hollow is rapidly expanding. Wise, Koleda, is everyone okay?...We've detected that the Hollow is rapidly expanding. Wise, Koleda, is everyone okay? / ...We've detected a sudden expanding of the Hollow. Belle, are all of you alright?...We've detected a sudden expanding of the Hollow. Belle, are all of you alright?‍)
Koleda: —AAARGH! Damnit! DAMNIT!
Koleda: What was the point of just us being careful?! They still got away, and the Hollow's expanding anyway! Dammit, dammit, if only I had...
Icon Dialogue Talk Koleda, calm down.
(ProtagonistProtagonist): (‍Calm down, Koleda. Give me some time to gather post-expansion data. I'll find them.Calm down, Koleda. Give me some time to gather post-expansion data. I'll find them. / Just stay calm! Give me some time, I can find them...Just stay calm! Give me some time, I can find them...‍)
Fairy: Collecting Hollow expansion data... The Hollow activity is immensely high, requiring the collection of a significant amount of data. Please ensure I have stable access to electricity, Second Assistant.
(SiblingSibling): (‍Well, I've stopped charging my console. That's all the electricity we've got, so use it wisely, alright?Well, I've stopped charging my console. That's all the electricity we've got, so use it wisely, alright? / Alright, I've unplugged my phone charger. That's all we have, so try to hold back a little if you can.Alright, I've unplugged my phone charger. That's all we have, so try to hold back a little if you can.‍)
Fairy: Collecting data... Currently collecting data from Master's surroundings. Lost item data... Bangboo activity data... Human voiceprint data...
(SiblingSibling): (‍...Hey! What does any of that have to do with the Hollow's expansion!? You better cough up some money for that electricity you are wasting....Hey! What does any of that have to do with the Hollow's expansion!? You better cough up some money for that electricity you are wasting. / All of this data is totally irrelevant to the expansion of the Hollow! Why are you wasting the electricity on it?All of this data is totally irrelevant to the expansion of the Hollow! Why are you wasting the electricity on it?‍)
Fairy: Master, I have captured a nearby human voice not belonging to that prior group. Now broadcasting—
Fairy: "... come... me, transfer student... over here... it's this way—$$%^&^*"
Koleda: That voice!
Icon Dialogue Talk Emmie?
(ProtagonistProtagonist): (‍Emmie...? But why is she here? Can you locate her coordinates, Belle?Emmie...? But why is she here? Can you locate her coordinates, Belle? / Emmie? Why is she here?! Can you track her coordinates, Wise?Emmie? Why is she here?! Can you track her coordinates, Wise?‍)
(SiblingSibling): I can, but I'll need some time.
Koleda: The worst case scenario would be if the expanding Hollow reaches the school, and Emmie isn't the only kid who gets caught up in it...
Icon Dialogue Talk We've got to check on the situation.
(ProtagonistProtagonist): (‍It's gonna be alright, Koleda. Let's retreat for now and check on the kids, then return as soon as possible.It's gonna be alright, Koleda. Let's retreat for now and check on the kids, then return as soon as possible. / Yeah. Right now, our priority is to check on the kids and make sure they're alright.Yeah. Right now, our priority is to check on the kids and make sure they're alright.‍)
Koleda: ...I got it. I'll go find Grace and find out what's happening.
Koleda: I'll head out then. Let me know if anything else happens, Proxy.

Notes

  1. Actual voice-over: 'Your actions have distracted the Ethereals.'
  2. Unlocks after distracting an enemy and getting caught again.

Other Languages

LanguageOfficial Name
EnglishBack to School
Chinese
(Simplified)
重返校园
Chinese
(Traditional)
重返校園
Japaneseバック・トゥ・スクール
Bakku Tu Sukūru
Korean학교로 복귀
Hakgyoro Bokgwi
SpanishRegresa a la escuela
FrenchRetour à l'école
RussianСнова в школу
Snova v shkolu
Thaiกลับสู่โรงเรียน
VietnameseQuay Lại Trường Học
GermanZurück zur Schule
IndonesianKembali ke Sekolah
PortugueseDe Volta à Escola

Change History

Version 1.4

  • The Commission's Subtype of [Investigation] was changed to [Story: Array].

Version 1.0

  • Back to School was released.

Navigation