Big SISTER | The Surge Wiki

The only difficult part of this boss, once you understand the safest moves/zones to avoid its attack is the fact that the hit box of some of its attack are utterly broken so you basically got to know that certain attacks hits 2x to 3x further and/or wider than whatever you're looking at.

Phase 1 is mostly about waiting for an opportunity that happens after half of its attacks. Each of the 3 attacks have moments where you can deal some hits in. The only thing to truly take note of is the laser which fire around 1 out of 2 attack and the fact that it resume to an attack with its remaining arm as soon as you destroy the other (which can sligthly alter the rhythm between the laser and attacks, but by that point its other arm should be close to destroyed anyway.)

Phase 2 can be quick or a major pain depending on which attack the welding arms does. The 2 issues with those are that they can hit multiple times in a row through a single attack (which can ignite you on fire) and the hit zone of those welding arm is much wider than their visual representation (it's like a sphere as large as the half of the arm itself) even being at a distance equivalent to it forearms' lenght away from its welding flame still hit.
If you get hit by multiple arms at once, it's an easy instant death.

Phase 3 can be dealt with by using a fast weapon with high energy gain and simple restore HP from said energy whenever you got to retreat back a bit (such as with the homing slam) and get hit by the lightning floor for a moment.
During phase 3, these's one glitch in the boss animations that seens to allow it to instantly do its frontal slam (the one it does if you get close while the welding arm are still active) after its homing slam which deals 90-95 damages and leave the player on the electric floor stunned long enough for the electricity to finish the job.

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Skipping the 4 arms is the best way to beat this boss. Just get up close and dodge anytime the head raises up, once I stopped trying to fight those welding arms I got it second try. also switched to firebug weapon from the PAX. core level was 43

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simple strategy for this is have your firebug throttle equipped and for phase 1, stand at the very back. this forces the boss to use the thrust attack which is super easy to dodge, then follow up with r1 r1 r2 for the flame circle and do that 2 times on each arm for easy phase 1. In Phase 2, you need to start in the back left or right corner and work down, hit fast and hard but don't deplete your stamina. for the head, just get to the base ASAP and use the flame combo again. when the head comes down, youi can just get in behind it and keep spamming this attack! good luck

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Have to equip extra heals just for this one fight because the boss will attack with an arm that isn't on camera the second your land animation ends and half of the time the laser fires immediately after while I'm recoiling. This fight would be really cool if I could ****ing start it.

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When I get too close to the bosses corners my camera spins to look at the arm across from me and then I die. I don't know if it's an attack that just one shots cause I cant see at all neither myself or the boss

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Anyone else notice how the head in the pic on this page looks sort of like the Big Sisters from Bioshock?

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The camera angle is the real boss here

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I didnt know i was supposed to lock on to the head during phrase 2/3.........cuz i was playing unlocked...........like in dark souls.........

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So, I found a bug that respawns the boss. I haven’t fought it again to see if doing so is game-breaking, though, so fair warning. So, I had the security armor and rig and was going back through the game opening security doors. I looked up the location of the doors and the one in R&D said something like, “as soon as you enter this area from the Big SISTR 1/3 fight, it should be right there.” So, I crossed the corpse of the Big SISTR, over to where you go after the fight. I followed the path, and, when I got to the drop down into R&D, I jumped in. Then, my game crashed. When I started it back up again, I found that the corpse path was no longer there, because Big SISTR respawned and was just there as if I didn’t already destroy her. Once again, I haven’t fought her again, so, I don’t know if doing so breaks the game. It’s just a weird bug I found.

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where is Big sister 2/3 and 3/3? LOL

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I'm late for the party, but I didn't even bother with arms in 2nd stage. Just get to the corner behind the head and they will disengage as they'll be out of range. The head itself is easy once you lock on it and get use to that far camera (use manual targeting). Swipe attacks won't reach you and when it's getting ready for that top-down hit just move to the opposite corner. Don't get pushed to the center and you'll be fine. The biggest problem is locking. It's dumb, that during first stage arms are switchable same way parts of the body are, but during the second stage arms and head are being treated as separate enemies (LB/L1 + left stick click on a gamepad). Hope it's useful to anyone.

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Honest this boss is too easy compared to every other boss, use single rigged and use your slide attacks, easy win even a caveman could do it, I did it first try on my first run and on NG+, hardcore kill is easy, ripping off its arms is honestly wasted time with just how quick she goes down, so yeah, as the saying goes, Git Gud, but you don’t need to be good when single rigs exist.

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Liquidator full set will weaken the energy attacks, phase one, move far back, you can see better and the sweeping blows won't get you. You can just rush to the head in phase three, its grapple isn't that powerful and liquidator can handle the element dmg.

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wow so this was the easiest boss so far and like the rest i used the pax also .

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Easiest boss in the game IMO

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Rolling under `the brain` in 2nd phase & attacking from behind (standing near its body basement) makes you invincible against grab attack. Still need to watch out for hands on sides though (if you did not eliminate them). Makes an easy fight.

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I Don't Know About Anyone Else but I Defeated This BOSS With The P.A.X Imperator With Ease

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Cut off two welding arms from the right side, then attacked the "Brain". Received Spitfire Rod V2.0

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Where to go after this boss?

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I went in completely clueless and ignorant and beat her on the second try, including the 2.0 weapon. Easiest boss in the game, I'd say. In the first phase the arms can't touch you if you stand in the corner diagonally apart from the respective arm. After that run to the head and beat her up. Best places to stand when not attacking are to the extreme left and right, as far to the background of the level as possible. Dodge like a maniac and attack her whenever she's not traying to grab you. I lost my lock mid-fight - might actually be easier than to deal with the horrible camera.

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For the hardcore kill :
Maybe the assumption that you must not kill ANY arm in phase 2 is wrong : I just watch this video (https://www.youtube.com/watch?v=tCPjCY97yag). He gets the v2 and kills 2 arms during phase 2. I read someone who didn't get it after killing 4+ arms. So maybe 2 or 3 arms is the max you can kill to get the v2. If so, kill the arms the nearest of the core, it makes the fight a LOT easier.

I will try it and update when done.

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Was able to defeat her in Hardmode...took me a couple of tries...the camera literally killed me several times...

Hardmode means ignoring Phase 2. Fighting the Head without killing the welding arms.
Its Hardmode because 2 welding arms are attacking you from behind.

With the right Strategy it was easy, since i still had the better 50% of my Potions.
I used the Firedevil V2 (from second boss)
Phase 1:
Stay at the back, touch the Fence. Thats when the Arms do their Lunge attack in the most time.
Dodge when they lunge and attack them with R1,R1,R2.
Phase 2:
Ignore
Phase 3:
At the first the Boss MAY kick you back once, but you CAN dodge that and he may miss you if you stick to the outer edge of either side.
Attack the Pole in the Back, where the Boss is mounted for about 200 dmg, you'll see a spark.
Then attack the Boss itself, Camera WILL lock on the Boss itself when you hit him once. Otherwise you might die of broken Camera >_>.
Dodge all attacks and try to say to the outer front (from your perspective) of either side, some attacks and the welding arms can't hit you there.
I just attacked the boss with my Firedevil R1,R1,R2 combo (Ring of Fire) and dodged...TRY not to hit the welding arms.

It is possible to used the PAX Imperator, but the Weapon is too slow for the Boss, making it much harder.

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Does anyone know the conditions to defeat the boss in order to get the spitfire rod 2.0?

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