Callisto Protocol Bosses & How To Defeat Them

Learn where you can encounter all bosses, their phases as well as general strategies for the bosses in Callisto Protocol!

Players might have issues while countering Callisto Protocol All Bosses, so getting to know the attack patterns and general tips might help in conquering them! The game features tons of mutants, biophages, and creatures lurking around every corner that you can imagine; however, when it comes to boss fights, it is utterly lacking.

Key Highlights:

  • There are a total of 2 main bosses in Callisto Protocol, the Two-Headed Brute Boss, and Ferris. 
  • The Two-Headed Boss will have 4 main encounters, first in Below, then in Colony, third in Tower, and fourth encounter in Tower as well! 
  • Ferris will show up in Chapter 7 for the first encounter and in chapter 8 as the final boss! 
  • The best way to get through boss fights in Callisto is by dodging, staying far away, loading up on ammo, and staying calm! 
  • The main benefit of completing all encounters and bosses will be that you will be able to finish the game fully! 
  • None of the boss fights are optional, and all 6 encounters need to be fought no matter what. 

Two-Headed Boss First Encounter 

First Encounter
First Encounter (Image Credits Exputer)

Kicking things off, the first boss that the players will mainly encounter will be when they are traversing through the sixth main chapter, “Below.” Now, we mention that this is the first encounter because the Two-Headed boss will be back to bite you sometime later as well. 

Whenever an automated voice starts talking about “Now departing, freight staging hub,” if you turn a bit to the back, there will be a giant fan that will start rotating; this is where the fun begins. The next second you know, the automated voice says, “Next stop, Arcas Station.” 

Starting Of First Wave

From there, players should encounter the first wave of opponents and start to waver in. these will be basic mutations that should not be all that difficult to take out. We would like to warn the players that there will be quite a lot of enemies they will have to face all at once. 

The enemies won’t spawn one by one; rather, they will continue to chime in smaller hoards. Players should refrain from using melee attacks, and one of the biggest reasons for that is simply because you might get ambushed. 

Instead, the best course of action will be to use your GRP to grip onto them and simply start launching them back into the turbine and turn them into a literal pulp. As the enemies are approaching you, if you are not able to time your GRP moves well, then you can also take help from your weapons, especially your guns, but whatever you do, just don’t bother using melee. 

There will be two main places from the enemies will spawn, the fan and close to the edge of the railings, both left and right; therefore, players should always be on their guard. If they start to ambush you from the railing, GRP those suckers and throw them into the abyss; however, if you are someone who wants all loot from them, then you can just use ranged attacks on them. 

There will also be an enemy that will pop down from the top, and you can simply shove them into the rotating fan or take them out using ranged attacks too. Hoarding up on ammo will be your main key to survival here. Therefore, it is crucial to have ample ammo as well as health injectors if necessary. 

One thing that players should know is that there will be about three chests placed on the right edge of the railing, the left edge as well as a bit towards the back of the main platform that will most likely have a bit of ammo so that you can reload and get ready for the main fight. 

Main Fight 

After you’re done taking out the smaller hoard of enemies, there will be a cutscene whereby the two-headed boss will appear behind the edge of the yellow platform. The Two-headed boss itself will be an advanced mutation, and in quite honesty, it’s not all that tough to take it out. 

Your best guess, even at this point, will be the stay at a distance and use ranged shots. It is basically a useless to try to attempt to run at the boss and try to launch out melee attacks for the first time. Therefore, reading the attack pattern deems extremely necessary. 

Shoot at its head consistently; it will continue to follow you, and you can take shelter behind the square box. At that point, it will lunge at you, and you can dodge the attack towards the right to avoid taking damage. 

Get back a bit, and aim at its body again, and this time it will fling its right arm at you, which you can dodge towards the left side to avoid damage. It lunges at you another time, and players need to step back even more, and after that comes a fling of his left arm. 

Shooting at its arm will cause it to become vulnerable for a short period of time, during which it will fall to the ground. Here you can go in with your melee attacks to cause it to take even more damage. 

After that, it gets back up, loses one of its heads, and starts heading for you, during which you can then dodge to the side once again, get at a distance, and continue to shoot with your gun. Its main focus at this point will be to fling its left arm consistently at you, so watch out for incoming attacks. 

It will alternate between flinging its arm to the left and then to the right, and at that point, it becomes really weak and falls down again, which is the perfect time to go in with melee and finish it off. 

Second Encounter 

Second Encounter
Second Encounter (Image Credits Exputer)

As for the second encounter, players will be able to come across the boss once again during the Colony chapter, and the boss itself will be near you while several buildings surround you. 

Now, when it comes to the actual fight, there isn’t all that much difference between the first encounter and this one. The brute will lunge at you, fling its arm, and you will need to dodge it perfectly, then switch to launching out ranged attacks. 

It then lunges at you three more times, and you can run into one of the huts in the back, which has a window that you can jump in and out of. At the end of the area, there will be a small explosive that you can pick up using GRP and launch at the boss, which will cause it to fall down, and you can use melee attacks here. 

There will also be smaller enemies that you will need to take out, so be aware. A total of 3 melee attacks will cause the two-headed brute to get back up on its feet, and it loses one of its heads. Run back a bit, and start using ranged attacks once again. 

As it continues to follow you, don’t stop running back to take shelter, don’t stop shooting at it, and for any reason, don’t get too close to it. It lunges two more times, both of which need to be dodged. 

The key here is to keep running from one end of the building to the other to divert the boss away from you for a bit so that you can get a bit of distance and shoot at it consistently without taking too many hits. Shoot at its leg to cause it to fall to the ground and end the sucker. 

Third Encounter 

Third Encounter
Third Encounter (Image Credits Exputer)

We are not nearly done, as there are two more encounters with the same boss again. The third encounter will be during the Tower, the eighth chapter. Players will be headed to enter the room in front of the giant metal boxes with red smoke and see the boss ready to devour them. 

Go to the bottom right of the room, and move along the three-lined metal boxes, and the boss will notice you. Keep aiming at it, and keep shooting out one after the other as it is running towards you, and when it gets too close, turn around and run back. 

As it follows you, shoot at its head and alternate between shooting at its limbs too. You will need to keep circling around the room in order to avoid the boss from getting too close. When it falls to the ground, don’t melee attack as we did in the first and second encounters; instead, turn the corner and shoot in between the gaps at it. 

The same thing will continue in a loop, a repetitive cycle of you running around the rooms, it following you, you shooting at it, it falls down, and then repeating. You can go in for a melee attack, but do it sparingly. At one point, it loses one of its heads and starts heading for you even faster, so players need to be even quicker on their feet. 

When it becomes weaker without one of its heads and falls to the ground, now is your chance to get in a few melee attacks. Shoot at its legs when it’s just gotten up to cause it to fall down once again, then go in for melee hits. 

Fourth Encounter 

Fourth Encounter
Fourth Encounter (Image Credits Exputer)

Moving onto the Callisto Protocol Bosses guide, in the final encounter, players will be able to find it in chapter 8 once again. Head through the veiny tunnel, and a small enemy appears, which you can simply GRP and throw into the spikes. 

Heading toward the medical ward will make you meet the boss once again. It’s the same thing, stay as far away as possible, and have ample ammo at hand. Alternate between shooting at the head, then the limbs, and the head again. 

Shoot at the middle, and it falls down, which is your time to go in with your stun baton to take out your rage at it, and the same thing repeats 3 melee attacks again, and it will be back up on its feet, but this time without a head. Keep running, use ranged shots, and eventually, it falls to the ground, where you can finish it off once more. 

Ferris First Encounter 

First Encounter
First Encounter (Image Credits Exputer)

Moving on, the next main Callisto Protocol boss you will encounter will be when you go over to chapter 7, Colony. Now, when it comes to the overall difficulty of the fight itself, the boss is definitely tanky, to say the least. It is also able to quote possibly one shot you. Therefore, the main key to survival during any encounters with Ferris will be to dodge

The first phase will begin when players enter a room where there is a hologram of Dr. Mahler, and she is talking about thousands of larvae and the general lore of the game. After that, Cpt Ferris will come out from a platform saying “521”, addressing Jacob directly. The cutscene ends, and Ferris is suddenly in front of you. 

Main Fight 

Whenever he starts lunging at you, he will find his right arm first, then left, then right, and then left again before he flinches back for a second, where the player can go in with melee attacks and even carry out a combo with their gun too. A small cutscene appears where Ferris grabs onto the player and then kicks you down. 

A repeat of the same punches occurs about 3 times before you hear Dani say, “I almost got it!” and Ferris grabs onto you again and pushes you. In a cutscene, You and Dani escape, and you need to exit the colony on the funicular, which then ends the first meeting with Ferris. 

Take this time to go over to the next reforge station to use credits on upgrades, pick up health gels, and stock up on ammo because the final fight is here. 

Alpha Ferris Ending Boss 

Second Encounter Ferris
Second Encounter Ferris (Image Credits Exputer)

Last but not least, let’s talk about the final Calisto Protocol boss that players will be able to encounter, which will be when they reach chapter 8. There will be a cutscene where Ferris comes out behind a door, and there will be a “final contest to determine the true survivor.” Ferris talks about his purpose and that “he’s gonna show you,” and the fight begins. 

He lunges at you and attempts to punch you, through which you can stagger him and then unleash a few melee attacks alongside your gun combo. He then grabs onto you and kicks you as he did in the first encounter. The same punching sequence continues, and at one point, a small cutscene appears where you attempt to attack him with the stun baton, but he blocks the attack.

After that, he will repeat the same punches you consistently need to dodge left and right, and then another cutscene appears, transforming him into a mutated version of himself. 

Fighting Mutated Form 

Now, when he transforms, he will form a small cacoon in front of his head, which players need to aim at its head. Ferris’ head will be the key to making him weaker and more vulnerable. Therefore, make sure to continuously outlaunch ranged attacks at it. 

After you do so, he will throw out a few projectiles, which you need to doge against. He runs after you while reforming his cocoon in front of him and continues to spit out projectiles that can seriously damage you. 

After that, he will also summon forth enemies that will explode if you get too close to them; therefore, make sure to stay far but still continue to murder them first so that you don’t die out too easily. You can also pick up the enemies using your GRP to simply shoot them away from you where they can explode but not hurt you. 

If you get too close to Ferris, he lunges at you, but luckily you can dodge to the right to evade his incoming attack. Continue to stay at a distance and continue to shoot right at the shield/cacoon that Ferris has formed. 

Whenever you end up breaking his cocoon, that’s the point when his projectiles launch out at you; therefore, keep in mind to learn this attack pattern. Know that if you also end up being too far, then he will run at you and fling its arm at you, which you can evade. 

There will be explosives that will be scarcely scattered across the general area, which you can use your GRP on in order to launch them at Ferris just to deal additional damage. This consistent pattern repeats until Ferris gets too weak, then a cutscene appears where he ends up falling down, and the boss fight ends. 


And there we have it! All encounters as well as general strategies to take to counteract each boss fight, and with that, we will wrap up our Callisto Protocol All Bosses guide! 

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Mina Anwar

Mina is a Gacha games guides writer at Exputer with years of writing experience. Xianzhou Luofu and Liyue Harbor are her second homes~ ~Jing Yuan/Mikito main <3

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