Arknights: Rosa in-depth gameplay analysis

Hello again! With what looks to me like a surge of attention to Rosa due to chapter 8’s presence (especially the drones), I figured that it’s a great time to talk about her (at least when I first write the post, I am pretty late with my plan because of CC#3). And Rosa certainly has an amazing kit going for her, opening up many other different strategies for the unorthodox doctors out there to play around.

Rosa is a Besieger Sniper that functions a little bit differently to most other sniper (just not as different as Rosmontis). She prioritises heavy enemies, and then ignore a large portion of their DEF, of which they tend to have a lot. Her best and most well-known kit is a multi-target, long duration bind over a massive area with a relatively short cooldown. This makes her one of the best units to stop enemies’ advance where your “delete button” units can’t rotate their skill fast enough or are busy somewhere else. And she can deal respectable damage herself, lessening the needs for bigger delete button.

Rosa, or rather, her archetype, has amazingly high base ATK stat, rivaling that of the Deadeye Snipers (the archetype with the third highest ATK in the game), albeit losing to them slightly. Despite that, their ATK rate is noticeably better than the Deadeyes at 2.4s per attack instead of 2.7s.

For a Single Target unit, it's actually not that great. But as always, it's mainly their skillset that makes an operator.

You’d think she’d have weaker defensive stats because of the high offensive stats, but not quite. Her HP is on the higher end of all the Sniper, losing only to the Spreadshooters, Flingers, Heavyshooters, and Andreana (a +HP trust cheater). I said “not quite” because her DEF is god awful and is one of the worst of the snipers (but Snipers in general don’t have high DEF aside from the short range one and Rosmontis). She also has no RES like most other Snipers.

Although, her defensive stats don’t truly matter because of her massive range, which I will be getting into soon.

Rosa’s cost is especially high for a single-target unit, further boosted by her 6* rarity: 22 DP cost at base, and 24 from E1 onward. 

Besieger has an exceptionally large range, unfairly large range even.

Lots of people dwell too much on the small gap between the Besieger and their actual range, but that doesn’t matter most of the time, and is actually beneficial.

Since their range is so large, they can just move back a bit and ignore the lack of close range. In other cases though, they can also be even more forward, using said large range to cover half the map, and given their strong offensive stats (and their own skills), they can reach and kill plenty of enemies before they even come close, or wound them enough that other Operators can finish them off. Both of the 6* Besieger (as of the posting date) also have nice forms of Crowd-Control to keep enemies within their range as well.

The far corner of the side area of this range is something almost no other unit can reach consistently. The combined width and length of this range allow so much flexibility in positioning that the lack of close range is pretty much irrelevant. Sometimes it’s even an advantage, as they would rather focus on new full HP enemies, rather than a near-death one.

Attacks the heaviest enemy first.

Before Rosa, and Besiegers as a whole, enemy’s weight are only important to the Shifter, where they shift enemies based on the difference between their Shift forces and Weight. Now it’s important to a bunch of other operators like those that has Levitate in their kit.

This is actually one of the best, if not the best, priority in the game.

Usually, the heavier an enemy is, the more of a threat they are. Most Elites and Defender-type enemies are weight 3 or 4, and Bosses are almost always at least 5 nowadays.

Meaning, this archetype, with their high physical ATK and decent attack rate, as well as their skills, will prioritize the actual threats in the map. They don’t waste time on basic mobs. Those can be killed by pretty much anyone.

Available at E1: When attacking heavy enemies (weight >= 3), ignore 40% of their DEF.

At E2 it increases to 60%.

In a way, this talent sounds limiting, because she can only ignore DEF of higher weight enemies. But in reality, the higher the enemies’ weight, the higher DEF they tend to have. All of the Defender-type enemies have weight 3 and above. Which means, when the talent gets to work, it works extremely well. There is one exception (because there is always an exception): the Rockbreakers, who have at best 100 DEF without any Contingency Contract risks. But then again that just means they take a lot of physical damage to begin with and need no DEF reduction.

That means, with her high base ATK, and now a talent that ignore a massive portion of DEF towards the enemies that have a lot of them, Rosa can deal with most high armored enemies without needing to reach for an arts damage source. I said “most” because there are occasionally some decently high armored enemies that are at weight 2 (especially with CC risks).

This also allows her a certain reputation as a boss focus unit, mainly because most bosses have the highest weight in the map. So Rosa would prioritise boss in those cases. The bosses that aren’t heavy is the number 1 boolied boss in the game, and normal Mephisto who’s teetering at weight 3. I personally don’t consider her a boss killer specifically, but she’s a great opportunity maker to kill bosses and can also contribute massively in damage.

It’s also pretty easy to recognize who’s heavy, because they also tend to look bigger than the rest. All big looking enemies are usually weight 3 and above, exceptions being Sarkaz Caster/Swordman and Fanatic (drunk hammer guy in CoB/Transport Hub).

You may think this is counterproductive with Angelina S3, which reduces enemy’s weight. It’s actually much less of a concern than you’d think. First, since it’s a global effect, it won’t change Rosa’s current attack priority. Second, the only weight level that is affected by this is weight 3, and they rarely have high RES. Guess what Angelina S3 does? That’s right, a 5-targets, massive area, AND decent arts damage. Third, Ange’s S3 is manual activation, meaning you can choose when to use it. While that does mean you need to spend more work to fit those skills together, the first 2 points help offset that a little bit, so you don’t have to worry about it that much. Plus using Angelina normally already required a bit more thinking than usual, so it’s not like you need way more than before by adding Rosa to it. 

Available at E2: When in team, all Ursus Student Self-Government members gain +8% ATK.

Potential 5 increases that by 2%, to 10%.

This is one of the few talents that works without needing to be deployed, but the effect is pretty not noteworthy. It only affects 4 operators so far (HG gib Leto): Zima, Istina, Gummy, and of course Rosa herself. Out of those 4, only Rosa can make great use of it with a really high base ATK, while the rest doesn’t have a high base ATK enough to make 8% meaningful (but obviously more ATK is always nice). It's just a lore-flavored talent, basically.

• Always available – Student Council President:

When in the Control Center, decreases morales consumption for all operators in the CC by -0.05/h for each Ursus Student operators in it.

The group effect is actually not that great. It’s the same as Ch’en CC skill, but affecting the one that are generally more needed elsewhere. Gummy with the amazing Trading Post skill, Istina to get clue 4 (it used to be rare when I first wrote the post, but now we also have op like Absinthe), and the only free one left is Zima, who has a dorm buff to regenerate morale faster after working with Rosa in the CC, if you choose to use this base skill.

The base skill itself is also not that great, synergy aside. So ignore it. Especially if you have the full R6S squad.

• Available at E2 – Prestige:

When in the HR Office, increases speed by 20%. Additionally, for every 1 contact made, increase chance of getting clue 4 (Ursus clue) in the Reception Room. (working time and recruitment slot improves the chance).

I still don’t know the exact details of this, and it’s actually really weird. We can safely assume that she gives more chance to get clue 4 as she finds more refresh tag. But it also said “working time and recruitment slot improves the chance” so that means the longer she works there, the more chance she’ll give clue 4? Does it add to the amount of chance that she gets from getting a refresh, or does it add separately? Then recruitment slots also affect it, which means HR level is also important (the same importance to Whisperain, for example). But do the slots innately give her more chance as well, or it also has to wait for Rosa to find a few refreshes?

Overall, it’s a bit too vague, and that was before we can even ask about the exact chance it improves to get clue 4. But if you’re lacking clue 4, this could be an option I guess.

I find it hilarious that a major identity of it is from Rosa getting a refresh, but the speed increase is only half of the normal accessible one (+20% instead of +40%), which reduces the rate of which Rosa get a refresh. 

Also, having more refreshes benefits you more in general so just sticks with the +40% one like Ethan and Orchid, both of which are free to get (as in gacha-less to get).

ATK +60%

30 seconds duration, 35 SP cost, 10 initial SP 

Auto Recovery, manual activation

Please don't.

Uhhh… Rosa has a really high base ATK to get a lot from +60%?

When you forgot to E1 Rosa or switch her skill in a squad before starting a mission with her.

ATK +60%, attacks 2 targets at once

60 seconds duration, 80 SP cost, 45 initial SP

Auto Recovery, manual activation.

M3 gives ATK +90%, 65 SP cost, everything else unchanged.

This skill has the same ATK +% with her first skill from level 1 to level 7, and coupled with the fact that this skill let her attack 2 targets at once and has near-similar uptime, means that you are 99% never going to need S1.

Do remember her massive range and massive ATK, attacking 2 targets at once in this case has more significant to it than say, Blue Poison. She can cover nearly the entire battlefield, to exaggerate, so taking 2 enemies at once allows her to contribute to the battlefield a lot more than you’d think even if you already have big burst DPS unit like SA, Surtr,…

If you have read this guide before, you'll remember me saying this skill is decent. It's still is fairly decent in term of damage output, especially with module, but it's just awful all around. Personally I prefer a shorter duration if it means similar uptime, i.e. I prefer 30s duration 30s cooldown over 60s duration 60s cd. Not only it's easier to time the skill rotation with enemy wave, but also the enemy wave never go on for 60s long. There is guaranteed waste to this skill duration.

The 1-minute duration is very nice, but the just as long cooldown afterward can feel anemic at time. So it means that, while the skill can potentially cover like 2 waves in 1 cast, it will also probably be down for just as long afterward, making it just as much as a 1-time skill (or retreat and redeploy). And before M3, the downtime is pretty massive.

But do remember her entire kit so far: massive range, prioritise heaviest, ignore DEF of heavies. And then add that with this skill granting a large ATK boost (and she also has a high base ATK), and 2 targets, mean that she can actually take care of the majority of elites enemy, can also clear mobs normally, and can also help killing boss. It really does a lot of damage and capable to deal with many types of enemy.

The real issues of this skill, are first, again, the cooldown, where you might even have to retreat (before the skill ends) and redeploy just to get the skill back up faster, and second, the existence of her third skill, which is just an amazing skill altogether. 

With the existence of her module, lots of people think that her S2 is better. Unfortunately, not only that her S3 is still the better skill with her module, but now the existence of Typhon also pretty much removes any need for this skill, because dealing damage is not what Rosa is best at anymore.

ATK +10%, targets 3 heaviest enemies in range, binds and attacks them once per second

7 seconds duration, 34 SP cost, 12 initial SP

Auto Recovery, manual activation.

M2 gives +20% ATK, binds 4 enemies, 32 SP cost, 14 initial SP

M3 gives +25% ATK, 8 seconds duration, 30 SP cost, 15 initial SP

It’s pretty easy to miss this, but the small %ATK boost is offset by the “attacks once per seconds” which effectively boosts her attack rate by 2.4 times. It also is a fixed-interval skill, and will always hit once per second if the skill is on going, ignoring -ASPD debuff and disarm. But will get cancelled early by stun or freeze.

Because of the fast interval, it deals a massive burst of damage during that 7/8 seconds. And by M3, it’s 125% of Rosa’s ATK per second for 8 times, and that’s by no mean a small amount of damage.

Bind is a great form of crowd control, and while binded enemies can still attack, with how large Rosa range is, she can easily reach someone and stop them far from ever reaching your other allies. Another argument is no enemies are bind-immuned (except for Kristen) while a lot are stun-immuned, making her bind almost always works as a crowd-control when you need it.

This skill might have a great stopping point at M2, making her bind 4 instead of 3 enemies, but I advise go all the way regardless because the bind duration is more important, plus lower cooldown means you get to spam more, meaning you have more chance to stop enemies. Plus it also has a faster first use after you deploy her, for helidropping or just to quickly get her skill ready, not too important though.

8s bind is also one of the longest control in the game. Again, almost no enemies are immune to bind so you're safe to launch this at whoever you're trying to stop and usually they will be stopped.

There’s a small time for the bind to actually hit, basically from when she fires the harpoon to when it hits the enemies. Most heavy enemies are slow, but if you’re using it to stop fast enemies (e.g. Lancers, enemies with extra movement speed risk,…), that’s an important point to consider. It will still bind and damage enemies even if they left her range, so just need to aim for them at the moment of casting the skills.

There are just so many ways to use this skill, and I love it for that. My favorite joke is that “Rosa appears more in my squad the less melee units I have” and it’s still technically an understatement on how great she can be.

The most basic is as a burst/nuke damage to 4 targets, sometimes it’s enough to let things die faster, especially the high DEF one (which are usually heavy). It has relatively low SP cost for this job too.

Another great way to use the bind is to allow more time to let other allies to do more damage that they otherwise couldn’t. Especially if they have a really really strong skill but is balanced by having weird range, some even has a straight range. You must have heard/saw the strat in CC#1 that let Rosa bind Crownslayer in the middle of 2 tiles and let Schwarz and Bagpipe to hit her with their 1-width tile in different line.

Do remember that, despite targeting heaviest enemies first, you rarely face too many heavy enemies at once, so you can still bind the lighter one (e.g. the Lancers again). When there are multiple enemies with the same weight, it follows the normal priority again, so you can still somewhat predict who it will bind.

Don’t feel like you have to wait for 4 enemies in her range to bind. If there is an extremely dangerous enemies to stop but no one else is in her range, just stop them first. You may lose 75% of the potential damage, but you also save your team and your sanity.

It's hard to go in details of such a simple skill though. You want someone stopped? Press this skill. The cooldown is short enough that it'll be ready in time as well.

My favorite record of this skill is to completely replace Angelina and Suzuran in CC#1, the 2 that were considered queens of the map, giving me this CC#1 Risk 19 Week 1 clear (I probably can push 20 if I reduce squad size and switch to bursting CS twice I guess, but the point stand). Another example is my CC#2 Day 10 New Street max risk (super speed day), where I just use her to stop the throwers to be killed by Firewatch and occasionally some Berserkers too. A few smaller examples are my R8-10 with 2 Snipers and CB-EX-8 with 4 Snipers, where Rosa’s role is simply to both kill the big guy and to stop the rushing guys (both the 2-block lance guy and the bulldozer) from advancing.

All are techniques that I have listed above so you can see what I meant, and there is one more great clear below too.

SIE–Ⲭ: Siege Equipment Training Device

• Stage 1:

DEF +30

ATK +60

Trait upgraded: Prioritise heaviest enemy in range first. When attacking enemies with weight 3 or higher, attacks deal 115% damage.

Analysis: Basic but powerful. Rosa especially benefits from this since her damage ignores 60% DEF anyway, and now it also deals 1.15 times the damage. By itself this won't be anything notable, but...

• Stage 2: (stats boosts do not stack, only replace)

DEF +40

ATK +78

Talent 1 changed: When attacking enemies with weight 3 or higher, attacks ignore 60% of their DEF and deal an additional hit of 40% of Rosa's ATK as physical damage. (new effect)

• Stage 3:

DEF +45

ATK +90

Talent 1 changed: When attacking enemies with weight 3 or higher, attacks ignore 60% of their DEF and deal an additional hit of 60% of Rosa's ATK as physical damage. (improved from 40% ATK)

Analysis: hoo boy what an addition. On first glance it sounds terrible as this is physical damage and the additional hit is less than 100% of her ATK, which makes it more susceptible to DEF, similar to Flinger's issue. But this is on a Besieger. Rosa's damage output is nearly double with this module upgrade. Both this additional hit and the stage 1 effect also benefits from +ATK buff, which both her S2 and S3 does. A lots of people think it's better with her S2, but her S3 with 4 targets, bind, faster rotation, and fixed interval remains superior to her S2.

The only problem is, Typhon is released on CN just before Rosa get this module on EN. Typhon straight up deals massively more damage. Rosa's module gives her only damage. If you have Typhon and are willing to use her, there is no reason to use Rosa for damage at all, making the module that gives Rosa more damage unnecessary.

If you don't care about that, then this module is very good for her. Like I said, it's just unnecessary and with how module block are still currently quite limited (even as of Typhon release), any possible saving on it is going to help in the long run.

Focus mostly on her third skill and obviously mastery it if you find the needs to. Her S2 isn’t bad either, but it’s not as good because her third skill is just more flexible.

Don’t worry too much about her range, it may be awkward at first, but if you got used to it, it’ll be much better (though that applies to anything I supposed). That is to say, the range is their strenght, not their weakness.

Now with Typhon released, Rosa's value dropped a bit. But the Besieger archetype is still amazing at what they are designed for, and Rosa's module does help pushing her value up. Her 8 seconds bind on a fairly short cooldown is still just that good, though becoming less of a general use skill and more into a specific scenario skill. 

My favorite ally with her (aside from Ely of course) is mainly Schwarz, because her S3 has a narrow range. I also don’t use that strat much, even in a lot of my ranged only clear. Rosa just synergizes with too many non-melee ops that I can’t decide, and Schwarz just benefits the most because of her awkward range, the same goes for Ifrit (but I hate casters, so she goes down 1 rank kek).

Fluff: Rosa’s S3 is extremely similar to Cliffheart’s S2 in many ways. It also throws sharp weapon attached to ropes to 3 enemies over a large-ish area to inflict DEF-ignored damage and inflicts crowd-control with a relatively short cooldown. But that’s enough meme I guess.

For those that have Rosa, how do you find her? For me, certainly she is nowhere “niche” that people tend to claim (the claims that I saw), but my playstyle as a whole is too unorthodox for me to ever try to dispute those claims. Admittedly, her binds aren’t really needed if you have either strong defenders or are capable of killing them with ease already. Her damage, while great, it's not that high compared to units that are designed with only damage in mind, even more with the powercreep.

Anyway, thanks for reading, and I’ll see you next time.