Arknights Warfarin Guide

by Windgesang

So you want to use Warfarin. You want your operator to heal huge damage and lay waste to the enemies. You want to let your operators spam more skills as the enemies dies in front of her, which let your operators to spam more skills. Welcome to this week’s “Operator highlights”. This old grandma cute lady of a medic shines on the battlefield thanks to the utilities that she can bring. I removed the “Underrated” part because like hell is Warfarin is underrated lol.


Warfarin is a 5* medic that does more than just healing. She can either give a lot of heal to a dying operator, or she can give one of your operators steroids to deal with enemies. Being a medic, she doesn’t really fight, only keeping her allies alive for them to keep on fighting. But this medic differs from the rest of the medic because she can also create situations where her allies thrives more, either by buffing their attacks, or giving them more SP to spam their skills.


– “Offensive” stats:

Warfarin (I’ll shorten her name to WFR for an easier time typing this whole post, which if it annoys you…good luck) has the second highest ATK stats of all the medic in the game (CN medics included), only losing to Shining. Which means that she heals more per “attack”, because she’s a medic not a fighter. All medics (Single and AoE and Wide range alike) has a healing interval of 2.85s per healing, so WFR has no edge here. If anything she loses out to the medic that has higher healing rate (like the infamous Ptilopsis, and to a lesser extend Shining and Sussuro).

– Defensive stats:

WFR’s HP isn’t notable among all medics and is on the lower end. Also I just found out that Breeze has the highest HP among all medics wutface. The same goes for her DEF, on the lower end of the spectrum. Lastly, medics don’t have any RES except for Wide-Range Medic and Nightingale, and since WFR aren’t those, she has no RES.

– Cost:

Single target medics tends to have higher cost than AoE medics, and WFR certainly is in line with it. 17 cost to deploy, and 19 at E1, same as Silence, who is another notable 5* ST medic.


Restore the HP of ally. Medics uses 100% of their ATK to restore the HP of allies, and if you haven’t notice yet, WFR is a medic. Her attack stat earlier was referring to this trait.


ST medics have the same range as normal AA snipers. A 3×4 area with WFR at the center of the 3 tiles edge.


Blood Sample Recycle. This talent restores 1 SP at E1 (2 at E2) to herself and a random ally within her attack range whenever an enemy die within her range (again). Which ally get SP given is random, which also means that if they’re full SP, or is using a skill, they can still be randomly given 2 SP, essentially wasting it since they wouldn’t receive it.

Important qualification to remember that the enemy that die need to be in WFR’s range, and the ally that is considered to be given SP also need to be in WFR’s range. And most importantly, remember that WFR herself will always get the SP (unless ofc when her skill is fully charged). What that signify is that her talent (and later on her skill) is not as random as people claim her to be, which is what the argument against her usually are, but still random for allies of course.

Because of the requirement that the dead enemies need to be in her range to trigger the SP granting talent, your melee operators actually cannot be on the edge of her range, since enemies blocked by them wouldn’t be considered inside her range. So you kinda need to pull your melee operators back a bit to use this talent. This could be a negative against her in maps that has little space for your other ranged operators.


Now here we are at the section that separates WFR from other medics. But first

RIIC skill:

Always available – Medic Expert α: Increase the training speed of medic in the training room by 30%.

This is the same as Executor last post, but for Medics instead of Snipers, because WFR is a medic, not a sniper.

At E2, this skill is upgraded to Medic Expert β, which then increases the training speed to 50% instead of just 30%.

With 50% increase in training speed, the training time is decreased by 33%. I forgot to mention this in Executor’s post, but any operators in the training room already increase the training speed by a small amount. Any skill that increase this further add to that speed increase, so in reality, a 24h training don’t quite get reduce to 16h, but further about 15.5h.

First skill: Emergency Triage

This is a simple one… or is it? Since WFR is a medic, her skills would assist in healing. This skill enhances WFR’s next heal to also heal for an additional % of the target maximum HP. Now, when this skill is ready to use, WFR will heal for 100% of her ATK + this % max HP of the healed ally. This skill is boosted further by the fact that it only activated when someone is under 50% HP. Yes, boost. Many people seem to think that the “under 50% HP only” is a limitation on a healing skill like on the 2 Healing Defenders. It may be true here and there, but for this skill, this is the way to improve the effectiveness of this skill. When would you need a % max HP heal? When your operator is dying of course. The limitation of under 50% HP comes in handy because that means this heal will be use when it is needed the most. This skill is the second “SP recover on attack” that I do for these guides, instead of the typical 1SP per second auto recovery (which is the reason I never said a skill has an SP cost, but rather a cooldown of a certain seconds). Since WFR is a medic, she doesn’t attack the enemies, instead gaining 1 SP every time she heals an ally, since it’s considered “attacking” an ally. At level 7, this skill restores an additional 19% of the target’s max HP, need 4 SP per use (as in, WFR need to heal someone 4 times to fill 1 charge), and can stores 3 charges (can you imagine this skill without the ability to store charges?). If you decided to up this skill to M3, you can increase the additional heal to 25%, and the maximum charges to 4.

Since the skill heals based on the target’s max HP, there’s a wide discrepancy between how good it is on operators. The higher an ally’s max HP is, the better this skill become. If someone who have a million HP managed to get down to 499999 HP, they will now be healed for 100% of WFR’s ATK + 190000. That’s pretty huge. But on the flipside, an ally with 300 HP going down to half will be receiving an additional 57 HP. Granted, if you have an ally with only 300HP, you’re either using Haze, or playing in CC with a certain risk. The thing is, it’s not just heal only a % of max HP alone, because WFR’s normal heal also applies as well. We have established earlier that Warfarin has quite the high heal value, since it uses 100% of her ATK value to heal ally and she has the 2nd highest ATK among medics. Which means, the skill allows WFR to have an easier time restoring someone’s HP to full after dropping below 50%, the thing that is already easily done for low max HP ally. Not just the effectiveness of the skill become lower as an ally’s max HP become lower, it also costs a charge of the skill where you wouldn’t have needed it that much. The skill can also sort of “reset” your healing animation, which mean you can do a normal heal first, then immediately perform this skill on another one that’s below 50%HP.

Her talent that grant her 2 SP every time someone dies in her range means that she gains half a charge of this skill whenever it happens. It’s both good and bad for this skill, the good thing is that it helps gaining charge much faster than most other operators with an ATK recovery skill.

The bad thing is that, most of the time, your operators won’t be constantly swimming under 50% of their HP. Which means, for a certain long amount of time in a map, WFR would probably be sitting there with 3 charges with nothing to do about it, especially when there’s a lot of weak enemies that can trigger her talent, which is wasted on herself when it’s full charge, since they wouldn’t be able to drop your allies to below 50%. When a certain threatening enemy come though, usually they would come solo, or take a bit too long to kill that at some point they would probably be the only one left. At that point, if you really need WFR’s S1 to keep someone alive, it won’t be enough to keep that one alive for a long duration of time, since, WFR need to perform a heal 4 times to gain 1 charge, which is about 12 seconds per charge without her talent. However, with 3 charges (4 with M3), the skill can perfectly buy you enough time to either kill that threat, or to reshuffle your formation to help reinforce the tanking ally.

Another good thing is, the allies that typically do the tanking/frontlining are usually Defender or Guard, which typically have high HP, so it’s a perfect synergy and is almost autonomous, as in, this synergy would automatically be running as long as you use the operators according to their roles.

Second skill: Unstable Plasma

This skill is the druuuuugs!!!! Anyway, this skill when active, grants to herself and a random ally in range a massive amount of % ATK boost for 15 seconds. No buff skills are without drawbacks however, and for WFR, when this buff is applied, whoever has it loses 3% of their max HP per second. At level 7, this skill grants +60% ATK, 3% HP loss per seconds, lasts 15 seconds (for a total of 45% HP loss), cost 60 SP to activate, with an initial SP of 45.

This is the first time I used “cost SP to activate” for an auto recovery skill, which by default grants 1SP/s (1.3SP/s with Ptilopsis E2, and 1.4/s for any eligible one). That was the reason I always use time for a cooldown of a skill rather than SP cost, since it’s easier to mentally figuring it. However, because of WFR’s talent, seconds of a cooldown doesn’t really work, so here we are with 60SP cost.

This skill’s HP loss effect, SP cost, and duration does not change with any skill levels or mastery levels. But, with each mastery, the skill gains an additional 10% ATK boost. At M3, this skill can grant +90% ATK boost to both WFR and an ally, AND, having an initial SP of 50. Which means after deployed just for 10 seconds or less, she can already activate the skill, turning it to a sort of a heli-drop skill. That ATK boost is really huge though as it’s almost double. For a quick example, Firewatch with 0 trust bonus at E1 Lv30 have 765 ATK, gaining a +90% put that to 1453.5, almost perfect for invading Constantinople.

It’s important to remember that, the 3% max HP loss is lethal, which means that if use incorrectly, an operator can die from overdose, which is not what WFR is supposed to be, since I don’t know if I mentioned this yet, but she is a medic, she’s supposed to save live, not ruin it. Another important detail is that, this skill always affects WFR herself. Since the skill increases ATK value, it means WFR’s heals are stronger during these 15 seconds. The skill also don’t go into effect immediately after clicking on it, only after a delay of about 0.75s. The ATK buff is additive, which means it only stacks additively with other ATK buff (ATK up skills or Sora’s buff), but it is calculated before skills or attack multiplier.

But wait, there’s more…just kidding we’re done with this joke. But seriously there’s more though. This skill is a one of a kind skill buff of this game, because of its nature. Typically, a skill with a duration means that the skill needs to run their full duration before it starts charging SP again for the next use, because skills cannot gain SP while running (the orange bar thingy). This skill once dropped, immediately finished the “duration” and start charging SP again. My haphazard guess is that the random nature and the fact that it needs to apply to someone else other than WFR forced the devs to code it to not interfering with her normal skill (Welp, Aak threw this theory out of the way now). In different words, this skill has no duration, but with a lingering effect of 15s. Because of this, this skill can start charging SP again as soon as you use it. If WFR can finish charging 60 SP, she can use it again, even if the old buff is still there, so you can have a 3rd person buffed as well. This is most notable when 30 enemies die in her range as soon as she uses her skill… yea like hell that’d happen. In Code of Brawl, there was a type of enemy that hit reaaally fast, so if you put WFR next to Liskarm while being attacked by 1-2 Brawlers, oh boi. I went up to like 4 allies buffed at once, including WFR herself, was pretty funny to see. The only other skill that begin charging SP again after use but have a duration are the summon-type of skill (Silence’s Medical Drone and Shamare’s Curse Doll) and they are under a similar vein, 0 duration skill but with a linger effect.

The buffs are separated for each of them, which also means they last independently as well. Remember what I said about heli-drop this skill earlier? WFR can totally be used as an emergency ATK boost to ally, provide that you still have a deployment slot open. Drop WFR → wait up to 10s → drop S2 → retreat WFR. The ally that receives the buff will still keep it even after WFR retreated since it is independent from WFR.

The skill, unlike most other instant active skill, does not cancel attack animation. WFR can be in the middle of her healing animation (either shaking her stick or jumping up), and the skill won’t affect anything, in fact, if you time it right, the skill can go into effect just slightly before WFR finish her healing animation, essentially boosting that heal with little waste in duration…ish.

The negative aspect of HP loss, when paired with someone, can be converted to a positive buff again. There are 2 operators that when they heal an ally, that healed ally gain 1 SP, but they need to actually gain HP in order to receive that SP. Guess what skill constantly reduce an operator’s HP?

The negative aspect of random selection, however, is a bit harder to circumventing around. When it comes to random, people tend to assume that it’s inherently bad, as in, there’s no way for you to use it as you want it every time. What if there’s no options that you don’t want? Let me explain, instead of relying on RNGesus’ blessing to grant you the scenario you wished for, try forming cases where regardless of which timeline you end up to, there’s no bad choice for you. For a quick and quite specific example, a single lane defending lineup of Specter in front, Blaze behind, Exu and Eyja firing from the side, all within Warfarin’s range. When all of them are all attacking at once, and you use WFR’s S2, there’s really no bad chance there, since it’s all big improvements. Basically, you’d want to create a win-win situation instead of praying and hoping. Now of course, if you’re using non-DPS defender, some other non-hardcore DPS, or people who cannot attack at time like Cuora, Myrtle, Angelina (with the exception of Nian’s S2)… then this skill is going to be awful. Bottom line is, you’re probably going to have to rework your formation (not necessary lineup) to maximize the usage of this skill, if you don’t want to have just one person in her range to guaranteed the buff instead, which is a strat I don’t advocate for in all honesty.

But there is a silver lining. If I haven’t mentioned it yet, WFR is already a decently strong medic without her skills. With this skill, WFR can transcend her role of being a healer to a hybrid buffer, which increases her usefulness over medic that are just medic. So, in case that you wouldn’t need her S1, but still need some slight healing, you can just bring her S2 to use whenever you want, since any improvement from there are just net positive (unless you spam the skill off cooldown willy nilly). People likes to associate buffing with meme-ing for some weird ass reason, but there’s absolutely nothing banning you from using buff in a normal run, regardless of memes, formation, or lineups.

There’s been many contentions on this skill, and her talent, in auto mode. The auto seed is saved or not and such… but I won’t get into it here, since this is not auto mode highlights, this is Warfarin’s highlights. Just remember to be more aware about this when using her for auto mode though, since it may or may not follow it completely. You can read more about it here and here.

A miscellaneous info that I once shown in the Firewatch post, was that, most instant active skill still has a duration, typically about 0.5s or 1s. What this means is that if said skill kills an enemy within WFR attack range, and of course if the skill user is also in range of WFR to trigger the talent, they still won’t receive any SP (WFR received SP while the one that do the killing didn’t). Basically, that orange bar running down stops the SP from coming in, and this actually also apply for auto-recovery skill with charges. For example, if Greythroat with 1 charge of S1 and 2 SP and fires a charge, when it’s over it’s still at 2 SP.

That should be it for the old cute vampire doctor of Rhode Island. I know she’s not exactly “underrated” for this series but I’m making this post about her for a planned future post I have in mind. For the next post of this series though, it could be either Cliffheart, Greythroat, Glaucus, idk maybe vote in the comment. I have quite a few more operators that qualified for this series, but then I need to use them a lot in order to know what they can do and such, which I didn’t. Maybe you guys can give some more suggestions in the comment.

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