Arknights: Mastery Priority Guide - Under Tides Update

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Oh boy oh boy oh boy!  It's finally here!  Rejoice because the long wait is over, but wave bye bye to all of your resources.  This banner is a doozy, and definitely the most resource intensive one we've had.

There are 11 justifiable masteries here.  Incidentally, there are 11 new skills here across four units so that's... all of them.  Considering it can take about 2 weeks for a f2p player to farm an M3 that's a very daunting prospect.  Much of the discussion here boils down to one thing:  resource management.  Honestly you can't go wrong with any of the skills here so the focus instead is on getting the best value you can.

Some quick business before we dive in...

This article specifically covers the new units from the Under Tides event, You can find the full version of the guide here, or on the banner below which covers all of the other noteworthy masteries in the game.

This is my first new banner update on Gamepress, so of course please let me know if you have any feedback.  New readers will find a brief FAQ and banner discussion in addition to the grades.  Though it may be a bit out of scope for the masteries, lots of people have found it useful.  And if you're unfamiliar with the grading system, be sure to check out the details at the bottom of the guide (same as the main guide).

One final note, I'll be adding a 'Look Ahead' section here, by popular request.  The goal is to help people trying to prefarm but my usual research rigor is not there (yet).  In a lot of cases the units are brand new without a major end game event to gauge their quality in.  The section is meant to be quick and easy, and very subject to change.  You can find it at the very end of this update.  Hopefully you find it useful.

FAQ and Banner Discussion

Q:  Should I pull?

A:  There has never been a banner I more strongly answered yes on.  Of course we have had good banners in the past.  Many I've strongly recommended pulling on, but this is the first in which there are two hyper meta 6★s.  Both Kal'tsit and Skadi are about as end game as you can get, and have a higher total odds than a standard rateup banner (at least until you get one of them).

Further though, very few of the upcoming banners after this are all that special.  Only two are particularly noteworthy.  Ch'alter is the most broken unit in the game, though Mizuki brings the overall value of the banner down.  Saileach's banner is quite good as well, though not really broken and still 5-6 months away most likely.  Beyond those two, there's little that stands out.

Holding some pulls back or not for Ch'alter is ultimately up to you, but there's not a lot of reason to pass on this banner!

Q:  Is Skadi, The Corrupting Heart (Skalter) really that broken?

A:  This question comes up a lot.  It's not a bad question if you only watch clears at the surface level or only take a quick glance at her kit.  Most other units that are considered broken have a very splashy direct effect that anyone can see.  Everyone can see why Surtr is broken by only watching her a single time.  Skadi is less obvious to the casual look though.  It's not always obvious what she is doing on the field, but she is most definitely having a large impact.

She makes everyone better.  Essentially everyone in her range gets upgraded a tier.  Mundane guards become Cornerstone units.  Cornerstone units become unholy monsters.  5★ DPS suddenly has more attack than 6★ DPS.  Everyone, including frail ranged units, becomes significantly tankier.  She pushes the threshold that units that struggle with armor can handle, and does so to a significant degree.  And the effect never ends.  Then she effectively replaces medics on top of that (unless incredible burst healing is necessary).  She does so much and such a small cost on the field that she changes the way you create teams and can approach stages.

So yes, she really is that broken.

Q:  How about Kal'tsit?  Is she that broken?

A:  Not really, no.  Don't get me wrong.  She is a top tier unit.  She is very powerful and flexible and can fill in a lot of team roles.  But she comes with drawbacks, and the niche she really excels at in True Damage is not always needed.  Without going to deep into it, she is a tremendous unit, but a tier off of the most broken.

Q:  What about Gladiia?

A:  With much respect to my beloved Bibeak, Gladiia is the best free unit we get by a good bit.  And she should be, given the rarity difference.  However shifters at large can be tough to use and their niche is often incredibly map dependent.  Gladiia is no exception there so she tends to grade as only an average 6★ (which is still really good considering she's free!).

Gladiia is very flexible though, especially given her tougher archtype.  She can fill in a lot of missing gaps on weaker teams.  She can't really be called mandatory or meta though, and she has one of the lowest E2 rates among 6★s per the latest NGA poll.

Q:  This banner looks really expensive... Assuming I get everyone, what is the minimum I should do?

A:  Well, the minimum threshold is up to you, but for a vast majority of players the answer will be Skalter S2M3 > Kal'tsit S3M3 > everything else by preference.

Under Tides - Deep Drown Lament

Skadi the Corrupting Heart

S2M3 S++ S++
S3M3 A+ S
S1M3 C C+

Unlike her base form, all of Skadi the Corrupting Heart's skills are worth mastery. She is the latest entrant into the growing M9-ables. Though like all M9s there are still skills that are a cut above the rest.

S2 is Skalter's standout skill. It does so much and going into all of the details is a guide worthy all on its own. I would argue it's one of the strongest masteries in the game, with only Surtr and SA tier masteries beating it out. Quite simply, it elevates your entire team to another level while nearly eliminating the need for medics at all. For just one example, a max level S2M3 Skadi gives Popukar better stats than an unbuffed E2 90 Blaze, and Skadi gives more stats to Blaze than she gets from all 90 of her E2 levels!

S3 is next up. It will be the skill you want to use when you need the buff army to kick into overdrive. The True Damage is nice too, especially with the deploy-almost-anywhere Seaborn, but it's somewhat weak and the skill overall has a relatively long cycle time. This is a VERY strong mastery though, but it does tend it towards more advanced situations while most story situations will prefer to stick with S2.

Last comes S1. It's the weakest of the three skills, though it is still very good. You can probably pass on mastery, even for advanced players. In the situations you would use S1, it is probably fine still at SL7. It's very hard to justify the mastery costs here unless you're a whale.


S3M3 S+ S++
S2M3 A+ S

Kal'tsit has two very good skills, but focus first on her S3 which is the most potent True Damage skill in the game. Most other True Damage skills have a significant drawback (Franka, not really True Damage I know, and Skalter on the same banner), limitations (Weedy), low total damage (Cliffheart), or limited uses (Amiya). Kal has none of those, doling out a ton of True Damage on a pretty short timer. S3 is her best skill, and the reason Kal is special in the meta.

Her S2 is a great mastery in terms of the gains, especially if you wish to use her for more general purpose since it allows her to operate as a pseudo cornerstone unit, but in the wider scope of the game, it fits in awkwardly. Given the involved restrictions of two deploy slots, micromanagement, and reliance on tile layout, it's rarely the best choice if the flexibility of Monst3r's fast-redeploy is not needed. Even semi established players with a decent unit selection will most likely want to redirect the resources elsewhere and just bring a ground cornerstone instead of Kal S2. However it is still a very good skill, and the fact Monst3r is essentially a fast-redeploy (with more block and better stats than any full FRD), means S2 provides a ton of flexibility that few others can match.

Kal's S1 is a usable skill, but probably the weakest on the banner. With so much else good, it's not worth considering.


S3M3 A- A
S2M3 B+ C+
S1M1 Breakpoint
S1M3 B- B

Gladiia is a tricky unit to grade. She's one of those units that can be incredibly powerful in the right situations, but only average to worse in the wrong situations. On top of that, like all shifters, she has valuable masteries regardless of power on account on the increased shift strength at M3 (you'll note almost all other major shift masteries are graded elsewhere in the guide). And on top of THAT she is part of a very expensive banner on which prioritization is very important while being super expensive herself! AND ON TOP OF THAT all of her skills are good!

Alright, I'm done being dramatic. She's a nuanced unit, but the grading isn't actually that hard. Pullers are one of the tougher archtypes in the game since pulling often does more harm than good if there isn't a hole to pull the enemy into (compared to pushers for stalling). And while Gladiia is a tremendously good unit for a free unit, she's only about average as a 6★ overall, so promoting her at all couldn't be called mandatory by any stretch.

Gladiia's S3 will be the skill most will want to focus on. It has a niche that no one else can do, and most teams will find useful (in addition to looking real cool). It is a really good stall that can be deployed at a good long distance, and one of the only skills good for 'bundling' mobs together. Although it's not quite a mandatory skill, it's the sort that will always be useful to have in the pocket, and gets a big upgrade out of mastery.

Her S2 is a very flexible skill. It's less overtly flashy than S3, and the niches aren't as unique, but it covers a lot of ground. It has high damage, multi-targeting, a wide range (only matched by Cliffheart), and good uptime. If you wanted Gladiia to be a regular part of your team, then this is the skill to go with, however people with even decent rosters will generally find better units to place in those roles. The grade here is relatively high since it is both flexible and has good upgrades, but most should treat it as a waifu only skill.

S1 is the best short-sp pull skill in the game. The charge stacking is a really ridiculous feature that overcomes the cycle time issues that can sometimes arise from such skills. However it's very map dependent. Pulling is not overly useful if there isn't a bottomless hole to abuse, unlike pushing which can find use in stalling otherwise. As a comp, the best short-sp push skill is FEater S1. If you haven't found cause to do that mastery, you probably shouldn't bother with Gladiia's S1 either.


S1M3 C C
S2M3 C C

It pains me to grade Akafuyu because she's my personal favorite unit in this banner. But ultimately I'm forced to come to terms with a weak archtype, a super strong banner on which nearly every other skill is a better investment option, and a long standing 6★ counterpart that's still better in most ways. She is quite strong relative to other 5★s, and newer players with weaker teams will find value in her strong self sustain, but at this point in the game that doesn’t mean as much as it used to.

Both of Akafuyu's skills are good, and if you raise her, the one to go for first will largely depend on how you play. I give a small favor to S1 since I personally feel the 0-block niche is an underrated and underutilized niche and it has stronger DPS. Unfortunately though, she gets relegated to waifu only grades.

The Grading System

Story vs Advanced

There are very few absolute answers when it comes to prioritizing upgrades. A major determining factor is what exactly your goals are. Now, there are actually many more types of players than these two, but the most obvious delineation as far as which masteries to think about comes down to the type of content you're most interested in clearing. If you only find value in first time story clears and risk 18 CC, then your goals will be different for someone looking to reach high-risk (25+) in CC.

Story - A story player is a player who is only interest in rewarded content.  This means all normal stages and challenge modes (without added personal challenges), risk 8 on CC daily stages, and risk 18 on CC permanent stages

Advanced - An advanced player here is any player interested in non-reward topics such as higher risk CC and more min-maxed gameplay or specialty clears.

A note on the topic of the Advanced grades is that these grades should not be taken as specific advice for a specific CC. There may be an occasional specific note to provide some context or example, but the intention here is to be more general than a particular event and prioritize skills that will be broadly useful in multiple scenarios. A skill appearing once in a high-risk CC is not enough for inclusion here as CCs tend to lend themselves to niche scenarios that can't really be planned for. Further still, Advanced grades encompass all min/maxed gameplay and do not, strictly speaking, have to be about CCs.

The Grades

S - These skills are the cream of the crop. They are skills that everyone with the unit should do and give a high priority to. Units with S tier skills get an outsized value from them, either because the skill is incredibly powerful or because it changes how the unit is used.

A - These skills are powerful skills that most players who have the unit should do. These are among the most powerful skills in the game, but less overtly overpowered than the S-tier skills.

B - These skills are reasonably powerful and worthy of consideration, but have a factor which hold them back. The impact may be relatively small for the cost, the unit may not be especially powerful already, the unit may not fit well into the meta, or there may be a better version available, among other examples.

C - These skills are strong enough to be noted, but should only be done by the most end game of players with nothing else to do. There's value in them, but in the end of the day, most players will have something better to be doing.

Breakpoint - Not a true grade, but a designator given to an M1 that gives an unusually large benefit. In most cases, these should be prioritized immediately after the E2, thanks to their low cost and high value. Note that there are many M2 and M3 breakpoints but they are not considered breakpoints for this purpose as the cost is much more expensive. Also note that some breakpoints on valueless skills are excluded as well.

Please remember all rankings here are considered independent of E2 priority, but do consider overall unit strength.  And most important, these grades should be treated as guidelines rather than absolute requirements.

Mastery Look Ahead

This is a section I've added for the first time and is one of popular request. I don't tend to do nearly as much intensive research into units until their release is close, so I am hesitant to make too many firm declarations here. However, there are enough people out there who are looking to prefarm the next unit, or just want a sense of what's coming up, that it's become worthwhile to add.

The summaries here come with no promises or guarantees (not that any of them do...). Please keep in mind that this commentary is largely cursory and my first impressions, and is subject to change. The odds of me being wrong here, especially on units that are only just released and have less events to their name, is much higher.

That said...

Carnelian Strong story mode unit, but pretty poor advanced unit. S3 moderately high priority, S2 and S1 maybes with more niche uses.
Kirara None. She's bad. Like, Passenger bad, but more forgettable too.
Indigo None. She's bad, but hey, boob window?
Bena Really interesting one. Looking forward to her a lot. S2 looks a lot better, but I’m not sure what sort of grades to be looking at yet since they aren't core to her use case.
Pallas Waifu only unit. S3 mid priority. S2 maybe. Most can skip entirely.
Ch'en the Hellalame None because she is a sin upon the game. Sadly, S3 overtakes TSS as the best mastery in the game.
Mizuki Waifu (heh) only. Requires more research. Probably S3, but maybe S2. Most can skip entirely.
La Pluma S++ cuteness but also a really really good unit. Potential M6. S2 is probably the better choice for its high burst shredding, but S1 is a solid pseudo-cornerstone sustain.
Tequila A good boy with good damage. S2M3 very high priority. It's a mini-SilverAsh you get for free, with a faster cycle time. S1 looks like a dud though.
Saileach She’s good, but the jury is still out on just how good. S3 high priority either way. We need a CC at least to see about S2. S1 is unlikely to be worth the cost except for the extreme min-maxed situations.
Mulberry The new sustained HPS queen. S1 definite mastery. Direct healing with little/no utility is limited though, so that will hold the grade down.
Roberta THE NEXT LOUD NOISES UNIT. Potential abusable niche, but we'll have to see. Even if she is, her skills may not matter much.
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About the Author(s)

Lost redditor, April simp, and Mastery guru