
Caster
Corroserum
★★★★★
Columbia
Introduction
Corroserum is a 5-star character in Arknights. Corroserum's class is Caster. Faction: Columbia.
On the combined Arknights tier list Corroserum is D tier, 386th of the 410 characters ranked, from where 2 community tier lists put Corroserum.
What Corroserum does
A
Caster who charges SP faster once she's gone 4 seconds without attacking.
Conductive Corrosive Blast adds 100% ATK and silences targets for 5 seconds, and she can switch it off whenever;
Focus Overload hits harder at +135% ATK but leaves her stunned for 10 seconds.
Profile
Corroserum is a male Phidia. His birthday is Apr 7, and he stands 172cm tall. Corroserum is voiced by FengXiu in Chinese, David Menkin in English, Daisuke Kishio in Japanese, and Kim Sin-woo in Korean. Jacknife drew him.
Stories
9Basic Info
[Code Name] Corroserum
[Gender] Male
[Combat Experience] Six Months
[Place of Birth] Columbia
[Date of Birth] Apr 7
[Race] Phidia
[Height] 172cm
[Infection Status]
Medical tests have confirmed that no infection is present.
Physical Exam
[Physical Strength] Normal
[Mobility] Normal
[Physical Resilience] Normal
[Tactical Acumen] Standard
[Combat Skill] Standard
[Originium Arts Assimilation] Excellent
Profile
Associate to Raythean Industries Experimental Prototype Engineering, serving as Assistant Director to a project group.
Currently dispatched to Rhodes Island per relevant agreements, carrying out technological exchanges as well as work in product testing, et al.
Clinical Analysis
Imaging tests reveal clear, normal outlines of internal organs, and no abnormal shadows have been detected. Originium granules have not been detected in the circulatory system and there is no sign of infection. At this time, this operator is believed to be uninfected.
[Cell-Originium Assimilation] 0%
Operator Corroserum shows no signs of Originium infection.
[Blood Originium-Crystal Density] 0.12u/L
You can plainly trust Raythean Industries' control over its R&D environments. That, or at least you can trust the project teams unwilling to abuse high-risk materials in the name of increasing their project's value.
Archive File 1
Operator Corroserum's work at Raythean Industries principally stressed technical participation in and support to the project team-internal R&D process. He, however, applied for a product testing dispatch assignment at the end of the project he recently directed, and came to Rhodes Island.
According to our investigation, a portion of Raythean Industries's project managers evaluate Corroserum's attitude towards work as 'earnest and responsible, but lacks passion.' We were initially somewhat perplexed by these evaluations, but after practical observation of Operator Corroserum's MO, we somewhat understand why they said what they did.
With a fine condition, Operator Corroserum is able to complete work assigned to him at a bewildering speed, attaining in line with required quotas, but on the flip side, he will not exceed his quotas. And after that—he'll put on his eye mask, lie back in his office chair, and begin his break at his desk full of reports just freshly inked to completion. Coworkers unfamiliar with him might misconstrue this; only related personnel actually aware of the work allotted to him know it's not because his workload is lower than others'.
But if it weren't for a necessity of duty, Operator Corroserum wouldn't lend a hand to his still-busy colleagues in his spare time, or submit proposals to improve the project. He simply takes it as granted that assigned work should be completed, whether the subject is himself or others.
Archive File 2
When discussing the weapons he uses, Operator Corroserum displays a rare interest.
'This is a target product we're required to test as part of our collaborative project, and explaining the technological issues that tie into it is a part of and duty of my work. Of course, I won't be leaking any specific information on its purchasers.'
People admittedly have misgivings about corrosive weapons, and it's hard to imagine that Raythean Industries' technology can actually develop a corrosive able to affect multiple common metals, disintegrate their structures, cause weapons and defenses to lose sufficient dependable function, and simultaneously guarantee its harmlessness to the human body.
But Raythean has guaranteed its safety in our contract, and we've attempted our own verifications within the labs. Our results may be surprising, but reasonable: this corrosive itself by no means has sufficient corrosive power, and its customized Arts Unit provides it amplification and direction—but this is only a rational explanation drawn from combining experimental results and information provided to us by them. We have no right to reverse-engineer, and we might not even be able to.
This handling method unarguably elevates the product's safety and technological secrecy, and has effectively met the requirements issued by the buyers to Raythean: negate enemy equipment while ensuring enemy forces can be captured alive and intact.
Archive File 3
After further communication between Operator Corroserum and Rhodes Island, we've become privy to some insider info.
During lunch break after a meeting, in Operator Corroserum's chat with the Doctor and a few operators, it was mentioned that the study of corrosion very rarely led to the development of corrosives in practice. Contrary to what many of us imagined, it's more often devoted to anti-corrosion tech and raising of product lifespan and reliability. Moreover, things aren't as cut-and-dry as that.
'Raythean Industries—no... any firm that receives orders for arms or equipment has to consider the issue of product durability, but no company would outright attempt research of anything 'long-lasting' or 'indestructible.' Granted, armies attached to higher authorities, e.g. Kazimierz's Silverlance Pegasi, don't fall under this. But in this era of rapid technological development, there's no motive for fighting forces requiring power to spend so much on custom equipment that can last for more than, say, three years. In my opinion, providing these projects with technological support is just a waste—project teams will even demand I appropriately lower the final product's durability, until it just so perfectly tips the line the stakeholders want, so they'll come and order something new next time. After running into these requirements time and time again, I stopped pointlessly squandering my care on those cheap things, and that, maybe, is why I didn't appeal to certain people. So it went until now, joining this 'Raythean Warbreaker' R&D team.'
What Operator Corroserum brought up here seemed far from under any strict NDA or classification, and we can assume the company had no reason to treat it as such, even if Rhodes Island has hit walls running into similar problems throughout its medical manufacturing pipeline and sales fronts. After all, whether in its internal or external affairs, every firm as a matter of course has its troubles and schemes. The current situation may not be requisitely optimistic, but we can only press forward through the mud with all we have.
Archive File 4
Despite our glimpse at Operator Corroserum's discontent with portions of work he managed at Raythean via his statements, the passion he's shown the few times he's been able to practically apply a project speaks just as loudly. From his project background, we can glean his fondness of choosing assistance roles; according to him, this lets him both avoid all flavors of difficult leadership and admin, and lets him comprehensively participate in project exhibition, the role of steering project goals and core technologies perhaps something he considers his home.
After arriving at Rhodes Island, the seemingly negligent look he's projected may just be his boredom from having no place to display his talents to his heart's content.
In regards to Operator Corroserum, in our paper agreements with Raythean, we obviously only have purview for work on relevant projects. But perhaps he secretly bears other hopes, that putting him in charge of directing his people might give us a greater knowledge of him, allow him to exhibit even greater impact in his specialty fields?
Promotion Record
Developing a weapon with corrosion as a primary means of attack requires the contents of research go far beyond corrosives and customized Arts Units.
For a weapon loaded with this corrosive, its composite materials must balance resilient makeup and good Originium Arts conductivity, another difficulty that needs overcoming.
Not just that, but after employing a nebulizer to effectively expand this weapon's attack surface and efficiency, this realizes a probability the weapon will cause accidental harm to allies, thus needing some quick and easy means of providing a defense to allied combat units. But none of this held Operator Corroserum back from wielding knowledge in his expert fields. He rapidly produced technical prototypes for a coating able to resist this corrosive, and in a short span of time, had it realized and put into practice. He explains this technology's greatest hurdle wasn't resisting the corrosive itself, but vying to make it just as harmless to the human body, in order to directly spray it on friendly equipment, lowering the upfront cost of using this weapon.
However, this project's manager later proposed another scenario: an enemy might just as well develop or steal this protective coating technology. Thus, he required Corroserum develop a corrosive that could get past this coating.
And not just that, but given the possibility this new corrosive technology could also be re-engineered or stolen, there may also be a need to proceed with developing technology that could withstand this corrosive in turn...
And following this, there might also...
Er, maybe we can try inferring at this point why Operator Corroserum chose to trial this weapon at the project's tail end, and provisionally leave a team where he could show his true strengths for once.
Stats
- HP310th of 4551,572
- ATK102nd of 455760
- DEF369th of 455120
- RES25th of 45220
- Block1
- DP cost426th of 44633
- Redeploy70s
- Attack interval425th of 4552.9s
At Elite 2, level 80, before trust, potentials and modules. Each bar is measured against the highest value in the Arknights roster, and the place is out of every character with that stat, lowest first for DP cost, Redeploy and Attack interval.
By promotion
- Elite 0 Lv. 1HP: 686ATK: 343DEF: 45RES: 10Block: 1DP: 30Redeploy: 70Interval: 2.9
- Elite 0 Lv. 50HP: 980ATK: 484DEF: 77RES: 10Block: 1DP: 30Redeploy: 70Interval: 2.9
- Elite 1 Lv. 70HP: 1273ATK: 638DEF: 107RES: 15Block: 1DP: 33Redeploy: 70Interval: 2.9
- Elite 2 Lv. 80HP: 1572ATK: 760DEF: 120RES: 20Block: 1DP: 33Redeploy: 70Interval: 2.9
Base values before trust, potentials and modules. Full trust adds ATK +90.
Trait
- Deals AOE Arts damage in a long line
Skills
2
Focus Overload
Manual trigger · Auto recovery · Unlocks at Elite 0LevelATK +135%. Corroserum is Stunned for 10 seconds after skill duration
- SP cost
- 30
- Initial SP
- 0
- Duration
- 30s

Conductive Corrosive Blast
Manual trigger · Auto recovery · Unlocks at Elite 1LevelATK +100% and attacks silence the targets for 5 seconds Can manually deactivate skill (skill can be deactivated at will)
- SP cost
- 40
- Initial SP
- 25
- Duration
- 25s
Talents
1Tactical Readjustment
- Elite 1
- After not attacking for 4 seconds, own SP recovery rate +0.2/second
- Elite 1 · Potential 5
- After not attacking for 4 seconds, own SP recovery rate +0.25 (+0.05)/second
- Elite 2
- After not attacking for 4 seconds, own SP recovery rate +0.45/second
- Elite 2 · Potential 5
- After not attacking for 4 seconds, own SP recovery rate +0.5 (+0.05)/second
Potentials
- Potential 2
- DP Cost -1
- Potential 3
- Redeployment Time -4 sec
- Potential 4
- ATK +33
- Potential 5
- Improves Talent
- Potential 6
- DP Cost -1
Modules
1
Unerasable (BLA-X)
Unlocks at Elite 2 Lv. 50StageStatsTraitTalent- Stage 1Stats: HP +150, ATK +49Trait: Attacks deal extremely long-ranged AoE Arts damage; damage dealt increases with distance, up to 110%
- Stage 2Stats: HP +175, ATK +55Trait: Attacks deal extremely long-ranged AoE Arts damage; damage dealt increases with distance, up to 110%Talent: After not attacking for 4 seconds, own SP recovery rate +0.6/second
- Stage 3Stats: HP +190, ATK +60Trait: Attacks deal extremely long-ranged AoE Arts damage; damage dealt increases with distance, up to 110%Talent: After not attacking for 4 seconds, own SP recovery rate +0.65/second
To unlock
- Deal a total of 100,000 damage with Corroserum (excluding Support Units)
- Clear Break the Ice BI-6 with a 3-star rating; You must deploy your own Corroserum, and use Conductive Corrosive Blast at least 2 times
Module record
Let me tell you a very boring story.
There are countless middle-class Columbian children living plainly favorable lives, who still attempt to assert their own individuality via what rebelliousness they've learned from others. Our hero for today is one such case.
The kids downtown never seem to exhaust their creativity or energy. Their skate tricks, graffiti art, and street rap hold a certain peculiar charm. No need for any means of intercity communication; it flourishes naturally in any urban center. Even the private school kids are captivated by this downtown 'ruff 'n' tuff stuff,' but discipline from their parents or teachers usually keeps them steering clear. They don't go out and experience the cool stuff for themselves.
So, our hero? His parents weren't for or against, they just didn't care, because our hero was a step ahead of the rest of his year. In whatever time was his own, he'd run off to hang out with those kids, but never actually joined in any of their activities. Maybe he was scared his classmates would mock him? Maybe he was scared that doing anything alongside the Infected would bring him trouble? Maybe he knew he wasn't like those kids, and in his heart raged all manner of emotions with nowhere to pour them? Who knows. All we know is that after the city passed a few new regulations quite unfriendly to the Infected, he put his self-taught knowledge to use and provided those kids some special new graffiti paints. If you ever tried to use water or any ordinary solvent to clean those walls, fresh anti-City Hall obscenities would show up over the works to disappoint you.
You think this story's actually veering on being interesting? Heh. Wait until I'm done. Yes, there's still more.
Years later, those downtown kids are grown-ups now, saddled with what City Hall gave them, including the 'necessities for life' bundled along with their experimental weapons. They're on Pioneer Teams. I hear the forces they're part of took down a group of wicked barbarians like they were spraypainting across a map, opening up an ideal site for Columbia to build a nomadic city. The street culture they once also pioneered hasn't vanished since their departure, either. You could even say it's popular among all the youth of the city now, as a form of recreation.
And what of our hero, you ask? He left the city, and never again encountered any graffiti from the throes of the heart, or skateboards in hand-painted livery. He found a job, and spends day in and day out either making more efficient weapons for his customers, or researching how to more efficiently destroy them.
Base skills
3
Corrosion Studies α
Workshop · Elite 0When this Operator is assigned to the Workshop to process elite material, the production rate of byproduct increases by 75%

Corrosion Studies β
Workshop · Elite 2When this Operator is assigned to the Workshop to process elite material, the production rate of byproduct increases by 80%

Corrosion Inhibition Tech
Workshop · Elite 2When this Operator is assigned to the Workshop to process Elite materials, any byproducts of T3 quality produced will be Oriron Clusters
Outfits
3
Elite 1
Default Outfit
Art by Jacknife

Elite 2
Default Outfit
Art by Jacknife

Leisure
EPOQUE/XXXI
Art by Jacknife
Store
Voice lines
38Show all 38 lines
- Appointed as Assistant
- Make the most of everything, hm? As you've given approval, I'll do my very best to provide you all additional joint effort and technological support necessary, within our agreement's scope, of course. Fortunately, assistant work was my exact vocation.
- Talk 1
- Rhodes Island's ambience is more assuaging than I'd imagined, at least personally speaking. After all, you typically feel medical firms would be nothing but dour to almost insipid researchers. Not to even start on your armed force to keep the Oripathy-related technologies and personnel safe.
- Talk 2
- In my time at Raythean, I took part in several project teams, but they mostly bored me. Obviously, one can't complain about their technological prowess, but if all it is is fulfilling orders to quota, without attempting to inject a little inspiration, doesn't work become just too dull?
- Talk 3
- You seem somewhat mindful of my manner of speech. Hmm, if possible, I'd like if you could bear with it. My last project team, whether superiors or juniors, all took up overly polite address that only sent communication efficiency to rock bottom. It posed a headache to me too.
- Talk after Promotion 1
- True, work calls for strict treatment, and serious accomplishment. But after work is over, you also need to understand keeping a balance and relaxing, which is what lets you adjust your own state and achieve glowing results next time in your work. Do you believe so, Doctor?
- Talk after Promotion 2
- Have you heard the observation that though many find satisfaction in neat, orderly things, there's a set that feels apprehension in a space holding the same qualities? Yes, every time a rest day passes and I return to a work station that's been tidied up, I feel suffering.
- Talk after Trust Increase 1
- A pileup of overdue reports and files just won't do. The paper shredder? No, Doctor, don't tell me you wouldn't want to try this environmentally-friendly corrosive, able to turn a ream of paper to pulp with a dropper's worth. There's no use? That's true. How about I launch a project to develop a papermaking machine utilizing this pulp?
- Talk after Trust Increase 2
- The impression you give may not seem quite like my project manager at Raythean, but there's some similarities. However, saying this with a wide open heart, you as a superior outstrip that unpredictable, outlandish black box of a crackpot project-intending plan-addled trickster genius by miles.
- Talk after Trust Increase 3
- Both Raythean R&D projects and working together with you have been delightful experiences. I'm finding myself torn between choosing, and I don't mean it as a pleasantry. Perhaps, you'd mock my greed? But people like us might just all be greedy. What's your view?
- Idle
- Only when you have finished everything at hand can you rest carefree and firm-willed. At this rate, I'm worried you'll... heh, whatever. With this little left, I can figure it out for you without any worry.
- Onboard
- Hello there, Dr. {@nickname}. Raythean Industries liaison, Corroserum. I'm sure you saw the relevant contracts and forms, despite your busy schedule. Now then, do share any upcoming workflow arrangements.
- Watching Battle Record
- Rhodes Island Pharmaceuticals Inc.'s battle records are more interesting than I expected.
- Promotion 1
- You've raised your evaluation of me? Thank you, this'll be good grounds to include when I apply for another tour here.
- Promotion 2
- True, it's worth taking joy in a project's smooth progress, but the evaluation you've given me, in my opinion, seems to have already outclassed my resume. That is to say, do you have further expectations of me, even greater than this?
- Added to Squad
- Ah, another assignment perfect for testing weapons. Of course, I'm very pleased to be working with you, Doctor.
- Appointed as Squad Leader
- This is an anti-corrosive coating spray, with no toxic side-effect on the human body at all. Given you were all willing to sign the disclaimer and participate in this test, I sincerely hope none of you become collateral damage due to irregular operation in this weapon's test.
- Depart
- The holiday's always over in the blink of an eye. Well, then, let's get to work.
- Begin Operation
- I'll be troubling you to make these test targets fall in line a little with our work, Doctor.
- Selecting Operator 1
- Do you have any additional directives?
- Selecting Operator 2
- You can order me for anything you'd like.
- Deployment 1
- Timed just like your simulation.
- Deployment 2
- The stressful test phase is now beginning.
- In Battle 1
- Can I make sure none of you will surrender just yet?
- In Battle 2
- I have an extra project here that needs all your cooperation for testing.
- In Battle 3
- I'd like to ensure you all persevere until I can gather enough data.
- In Battle 4
- Of course. This is part of work, too.
- 4-star Result
- Doctor, this has thrown a slight wrench in things. After all, you've obtained combat results beyond expectations, and made it marginally more difficult for my assessment of weapon performance limits to be universal and objective. I'll have to increase the quantity of test samples to ensure accuracy... was that in your plans too?
- 3-star Result
- A pleasing result. It seems once we return and I finish collating this data, I'll have some spare time for free movement. Well, then, do you have any free time coming up, Doctor?
- Sub 3-star Result
- Not too ideal in terms of results. Deployment tactics still have room for optimization. Don't you think so, Doctor?
- Operation Failure
- Let's not feel down, Doctor, you will find a solution to break this deadlock. After all, you'd like the reports we'll be writing to be worth more than scrap paper, wouldn't you?
- Assigned to Facility
- Is there anything I'd be able to help with?
- Tap
- I wouldn't trouble you with a matter this small.
- Trust Tap
- Doctor? I assume you're there.
- Title
- Arknights.
- New Year's blessing
- Happy New Year, Doctor. I'm very glad I don't have to confront those nightmare piles of annual reports here at Rhodes Island. It seems quite a few Operators have requested advance leave to visit family at home? Well, then, do you have any upcoming plans for this provisionally idle time?
- Greeting
- It's nice to see you, Doctor.
- Birthday
- I apologize, Doctor, I'm currently working. If you wanted to chat, you'll have to wait until I'm on break. Oh, yes, I left your birthday present on your desk early this morning, if that's what you wanted to talk about, I'd be very happy to sit down with you at dinner this evening.
- Anniversary Celebration
- I originally came to Rhodes Island to test weaponry and nothing more, but your command never ceases to demonstrate the importance and value of people. I've certainly learned very much from it... So, the idea of formally joining Rhodes Island may be a decent one. Doctor, can we have an honest chat about your terms of employment for any job-hoppers?
Upgrade costs
Open in the plannerPromotion
- Elite 1
Caster Chip ×4
Polyketon ×4
Oriron ×3
LMD ×20,000 - Elite 2
Caster Dualchip ×3
Optimized Device ×5
RMA70-12 ×10
LMD ×120,000
Skill levels
- Lv. 2
Skill Summary - 1 ×4 - Lv. 3
Skill Summary - 1 ×4
Damaged Device ×4 - Lv. 4
Skill Summary - 2 ×6
Orirock Cube ×4 - Lv. 5
Skill Summary - 2 ×6
Sugar ×5 - Lv. 6
Skill Summary - 2 ×6
Orirock Cluster ×5 - Lv. 7
Skill Summary - 3 ×6
Coagulating Gel ×3
Oriron Cluster ×2
Mastery: Focus Overload
- M1
Skill Summary - 3 ×5
Optimized Device ×2
Oriron Cluster ×3 - M2
Skill Summary - 3 ×6
Orirock Concentration ×2
Grindstone Pentahydrate ×7 - M3
Skill Summary - 3 ×10
Crystalline Electronic Unit ×4
Manganese Trihydrate ×3
Mastery: Conductive Corrosive Blast
- M1
Skill Summary - 3 ×5
White Horse Kohl ×3
Aketon ×5 - M2
Skill Summary - 3 ×6
Polymerized Gel ×3
Orirock Concentration ×7 - M3
Skill Summary - 3 ×10
Bipolar Nanoflake ×4
Manganese Trihydrate ×3
Module: Unerasable (BLA-X)
- Stage 1
Module Data Block ×2
Polymerized Gel ×3
LMD ×40,000 - Stage 2
Module Data Block ×2
Data Supplement Stick ×20
Optimized Device ×4
LMD ×50,000 - Stage 3
Module Data Block ×2
Data Supplement Instrument ×8
Orirock Concentration ×5
LMD ×60,000
How to get Corroserum
Recruitment & Headhunting
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