The Complete Boss Fight Guide for MIO: Memories in Orbit

Introduction to MIO Boss Battles

Boss fights in MIO: Memories in Orbit are more than just skill checks - they're the core of your progression. Each of the 19 unique encounters rewards you with essential abilities and items that unlock new areas and change how you play. This guide breaks down every boss, from the early-game brawlers to the secret ending challenges, giving you the strategies and preparation tips you need to conquer the Vessel.

Boss fights in MIO: Memories in Orbit aren't just tough encounters - they're the main way you actually get stronger. The game throws 19 unique bosses at you throughout the Vessel, and each one demands a different approach. Some you'll hit as part of the story, while others are tucked away in optional corners, but here's the good news: none of them are missable. If you rush the main plot and worry you missed something, don't - you can clean house after the credits roll.

What makes these fights matter isn't just the challenge; it's the loot. Every boss drops something that opens up new paths or abilities. Take down Egis and you'll score the Silo Access Badge, which means you can finally crack those sealed silos you've been walking past. Beat Crow and you unlock the Harvester ability, completely changing how you collect resources. These aren't participation trophies - they're your keys to seeing everything the game has to offer.

The devs scattered these bosses across the Vessel's biomes at specific moments, so you'll never go too long without a skill check. And since you can tackle them in pretty much any order you want after a certain point, your progression feels personal. You're not just following a trail; you're building your character's power set by choosing which fights to prioritize.

Essential Pre-Boss Preparation

Boss Preparation Tips

You can't just stroll into a boss fight and expect to come out clean. Before anything else, you need your movement abilities locked down - Dodge and Sail are non-negotiable. Dodge is what keeps you alive, letting you slip through attacks and find those precious counter windows, while Sail gets you out of bad spots fast when the arena starts filling with hazards. Without both, you're basically a sitting duck.

But here's the thing: all the mobility in the world won't save you if you're running on fumes. That's why Harvester is just as critical - it fuels your entire economy by pulling Nacre from sources scattered through the Vessel. More Nacre means more upgrades, which means you actually stand a chance.

Speaking of upgrades, Nacre Basins are your best friend before any big fight. These healing spots let you top off and grab last-minute upgrades, and you should prioritize anything that boosts your damage or movement speed. Modifiers are where you can really tune your build, so don't be afraid to experiment with combos that fit your style - whether that's hitting harder, tanking more, or moving faster.

And sometimes the game actually throws you a bone. Right before the Egis fight, there's a Nacre Basin hiding behind an icy gate just above the arena, specifically there for last-second prep. For Flora, make sure you've got Dodge ready to go - you'll find it in Aviaries Passepartout, and it's essential for that fight and others like Acat. Meanwhile, Atmos spams rapid-fire ice bullets, and Sail (grabbed from the Strange Tube at the top of Bell Tower) is highly recommended for positioning and dodging, though you can survive using core movement abilities like jump and dodge.

Early Game Bosses (Stages 1-6)

Egis - Worn Out Sentinel

Egis is your first real test, and trust me, he doesn't pull any punches. This close-range brawler hangs out in the Dwellings area - specifically down a slippery icy path in Apartments L2 - so you'll know you're close when you see the arena.

Egis is all about aggression: fast movement, sudden teleports, and spike attacks that'll keep you on your toes, which means you need to stay above him as much as you can. Watch for him to rev up like a runner about to bolt; that's your cue to jump. The good news is there's a Nacre Basin for healing located just above the battlefield, though you'll need to break through an icy gate to reach it. Take him down and you'll snag the Silo Access Badge, which opens up new areas to explore.

Crow - Automated Reaper

Crow is your third major encounter, and he's a whole different beast - think less 'tanky robot' and more 'teleporting nightmare.' To find him, you'll need to head to the Severed Spine area, make your way right toward the Haven, and then it's a vertical climb using flowers and Hairpin grabbers to parkour your way to his lair.

This fight is built around aerial pressure and teleporting strikes that'll test your composure. The arena shifts as he zips around, but his pattern is consistent: when he drops to the ground for his Ground Slam phase, that's your window to attack. During aerial attacks, just focus on evasion. His second phase speeds up the tempo but follows the same rhythm, so don't panic. Beat him and you'll earn the Harvester ability - a 'hit recharge' skill that'll change how you approach future fights.

Flora - Sentient Pearltrap

Flora's an early encounter, but she's no pushover, and you'll find her in the Feral Undergrowth through a door to the right of the Attuner save point. This fight is basically the game's way of saying 'you've learned to jump, right?' because it tests your mastery of jumping, double-jumping, and aerial attacks.

When Flora's vines come out, move to the left side of the screen and be ready to jump. More importantly, listen for the audio cue - a distinct screech that signals a poison attack is coming. The Kinetic Thrust Modifier can really help here if you've got it. The real prize for beating Flora is the Aviaries Passepartout, a key item that lets you access the Aviaries area and, more importantly, the Dodge ability. Trust me, you want this.

ACAT - Nacre Engraver

ACAT is optional, but he's worth seeking out if you're up for a challenge, though fair warning: having the Dodge ability from the Aviaries isn't just recommended - it's practically required. You'll find him on the left side of the map by taking a long icy slide and riding an elevator to the top-left area.

This fight demands patience and positioning over raw reflexes, so slow down and focus. You'll want to bait his attacks with side-to-side movement, jump to avoid ground attacks, and stay grounded when he goes aerial. His Charged Dash can be avoided with the Hairpin ability - just lift into the air and move out of his path. There's no reward for winning, but it's a great skill check.

Calderon - Unyielding Furnace

Calderon is a spectacle - four arms means four times the pain, but also four times the telegraphing, so you can actually see what's coming if you're paying attention. You can find him in Foundations by interacting with a fake container.

This battle is all about pattern recognition and smart use of your dodge. Watch his claws: when they glow red and rise above his head, he's about to strike. Attack his head when you can, but play it safe. The second phase introduces updrafts that lift you into the air, changing your movement speed and even causing icicles to rise instead of fall. Your best bet is to hang out in the top corners and only drop down when it's safe to attack from underneath.

Atmos - Weather Control Unit

Atmos lives in a windy hole next to an elevator in Foundations, and true to her name, she brings the weather chaos. The Sail ability, found in the Strange Tube at the top of the Bell Tower, is highly recommended for positioning and dodging, though it is not an absolute requirement for survival.

She starts as a snowman, which gives you a brief window to deal damage before she transforms. During the transformation, stay close and keep the pressure on. Once she's in her true form, the Sail ability becomes your best friend for gliding over those projectile attacks. This fight is pure high-mobility madness with homing movement and constant pressure, but you've got the tools to handle it.

Mid-Game Bosses (Stages 7-12)

Nabuu - Keeper of the Breath

You'll find Nabuu in Haven by jumping left off the main platform, and this deer-like creature is way more complicated than it looks. The fight has multiple phases that completely change the rules, which means you can't just button-mash your way through.

During the ground phase, you want to stay right underneath Nabuu and go for the chest - this position avoids most of its attacks while letting you deal consistent damage. But here's where things get weird: when the flood phase starts, Nabuu jumps to the background and you're suddenly dealing with rising water and explosives everywhere. Your job is to attack the purple flowers to stay afloat, so keep an eye out for them and don't panic.

Watch for the white glowing strands that appear before its horn attacks - that's your warning to get ready for strikes from the ground or sides. Nail this chaotic fight and you'll earn The Breath, a Pearl fragment that's absolutely worth the trouble.

SAWLONG (Chase Sequence)

SAWLONG isn't a boss fight - it's a chase sequence, and you'll run it twice: first in The Vaults, then again in The Pit. Think of it like those boulder run scenes from other games, except you're using almost every ability you've unlocked so far.

Your success here isn't about raw speed; it's about memorizing the route and nailing your reaction times. If Sawlong catches up to you, it isn't because you weren't fast enough - it's because you didn't know what was coming next. So focus on learning the pattern rather than rushing, and you'll make it through both encounters.

Anra & Dr Halyn - Anti-Rat Weapon

This two-stage Lab fight feels like dealing with a malfunctioning experiment gone wrong, because you're fighting a robot named Anra before Dr. Halyn himself steps in.

In Phase 1, stay glued to Anra - this kills most of the projectile attacks right away, and you can just dodge through the melee strikes. Between phases, Anra gets a shield, but you can break it by targeting the yellow orb in the mechanical hand. Once that drops, Phase 2 begins and Dr. Halyn starts slamming the ground while Anra's dead body hangs in the hand. Keep dodging those ground pounds while you damage the corpse, and you'll close this fight out.

Friends (Wall-Climbing Boss)

The 'Friends' fight takes place in Metropolis while you're forced to climb a wall, and honestly, it feels super awkward at first. Your timing gets all thrown off because you're thinking about climbing instead of combat.

The trick is to stay close to that slimy blob and just keep hitting it. When its gooey extremities start covering the screen, don't run - attack them directly to clear the hazards. Mastering the coordination between climbing and attacking is everything here, so once you get that rhythm down, the fight becomes way more manageable.

Lombre - Intrusive Fertiliser

Lombre in the Feral Undergrowth lower area is a dodge-timing test disguised as a boss fight. This slippery enemy has deceptive patterns that'll punish you if you get greedy.

Mostly, Lombre digs through the ground with clear visual clues showing where he'll pop up - just avoid the spot and attack when he stops moving. Occasionally he'll leap from the side and slide across, so dodge that and get your hits in when he hits the wall. Mid-fight, he drops poison rain with only one safe gap, and if you miss it, you'd better be ready to dodge-roll like your life depends on it.

Vlad (Circular Arena Boss)

Vlad's fight happens in a circular arena that's basically a death trap, and he doesn't even attack you directly - instead, the walls themselves spawn spikes and projectiles. You'll be attacking his central body the whole time while playing a deadly game of environmental awareness.

When the walls vibrate, they're about to spin, so you need to jump immediately to avoid the spiked sections. On top of that, electrical currents add another layer of chaos to track. Keep your focus split between damaging Vlad and watching the arena edges, and you'll make it through.

Late-Game Bosses (Stages 13-17)

Ancile and Targa (Dual Boss)

Ancile and Targa are basically Egis on crack - way faster and way more aggressive, which means you can't play it safe like before. While they're together, the good news is they move mostly in unison, so you can just focus fire on one until it drops. But once they split up, you're in for a world of hurt. They'll keep the pressure on with almost zero downtime between attacks, so you'll need to keep moving constantly if you want to survive.

Debby (Disappearing Floor)

Debby's fight in the Crucible is one of those classic disappearing floor nightmares you've seen in other games, but that doesn't make it any less brutal. The explosives she drops will chew through the platform underneath you, which means you've got to watch your footing carefully and use your double jump to clear the bigger gaps. Here's the trick though - when she starts that rapid-fire projectile attack from the edge of the screen, you can actually position yourself to land directly on her, which lets you deal damage the entire time she's stuck in that animation. Just don't forget you'll need to beat her if you want to save Mel in the Redacted area.

Poltergates (Summoner Boss)

Poltergates in Foundations' Metropolis region is a proper summoner fight, and getting to him is half the battle - you'll need the Striders ability to wall-crawl through a secret passage first. Once you're in, he doesn't just throw two versions of himself at you right away; he starts by spawning a few regular enemies from the outside world to soften you up. Then things get messy. Unlike Ancile and Targa, his twin forms move completely independently, so you can't just focus one down while they mirror each other. You'll be juggling both at once, and watch out for the aerial slam attack from one while you're busy with the other - it'll catch you off guard if you're not careful.

Sol and Vin (Sword-Throwing Duo)

Sol and Vin in the Promenade start the fight by immediately shrinking the arena down to that tiny center circle, so you're stuck combining jumps and dodges just to stay alive. The pattern isn't too bad once you see it - one swings while the other slams, so you can read their tells and time your counters. But when their health hits zero, the entire floor vanishes, and that's when you break out the Hairpin ability to float indefinitely. In that final phase, your only job is to stay in the air and only attack when it's completely safe. Nail this fight and you'll walk away with the Black Widow modifier, which is absolutely worth the headache.

The Keeper of the Heart (Final Boss)

The Keeper of the Heart in the Nexus is the final test, and it's a marathon, not a sprint. This thing has the biggest health pool of any boss in the game, so you're going to need to learn its jab, projectile, and slam patterns inside and out. The key is patience - only go for damage after the slam attacks when the boss stays grounded the longest. Since this fight drags on forever, you'll want every bit of protection you can get. Stack Protective Coating to the max and definitely equip the Protective Overlay Modifier before you even think about walking in there.

Secret & True Ending Bosses

If you thought the base game bosses were tough, these final challenges are a completely different beast. Both require serious legwork before you can even step into the arena, so here's what you're actually getting into.

True Ending Boss (Spoiler)

This is the real final boss, but you can't just waltz up to it after beating the story. First, you'll need to collect all four Pearl fragments - The Blood, The Eye, The Breath, and The Hand - which means scouring every corner of the map and probably checking a guide for the ones you missed.

Once you've got all four, you'll need to head to the Crucible area. You must first complete the six Crucible trials and then speak to Tomo in the center to trigger the final boss fight.

And that fight? It's the most challenging encounter in the entire game, with attack patterns so complex you'll need a few attempts just to learn the tells. But if you can pull it off, you'll earn the Welcome Home trophy and see the True Ending, which actually makes all that suffering worth it.

Secret Ending Boss (Post-Credits)

Think you're done after the True Ending? Not even close. The secret boss is locked behind a distinct path - you'll need to progress through the main story to gain the 4 Voices, defeat the Hand boss, and find all 12 Candles hidden throughout the game. These aren't just collectibles either; each one reveals more about the story, so you're basically piecing together the full narrative while hunting them down.

After you've lit every candle and met the requirements, a new post-credits challenge opens up. This isn't a simple rematch - it's the ultimate test with completely unique mechanics that'll force you to unlearn some of your old strategies.

Beat it, and you'll unlock the Tribute trophy plus the Defective Core Modifier, which is basically the game's way of saying 'you've mastered everything.' Fair warning: this one's for completionists only, so don't burn yourself out trying to rush it.

Boss Location Map & Navigation Tips

Interactive Map & Exploration Overview

You won't have a map when you start, which means the Vessel feels like a proper labyrinth at first. Your first priority should be finding Shii in The Spine area above the Nexus hub, but here's the catch: they're drained, so you'll need to donate raw Nacre droplets to their pond just to unlock basic mapping features. The unlock happens in two stages, which means you won't get everything at once. First, you get a stationary map that only works at Shii's pond, but when they're fully rejuvenated, you unlock the portable version accessible via pause menu anywhere. Trust me, you want that portable map ASAP because it'll save you hours of frustration and backtracking through the ship's maze-like corridors.

Fast Travel System & Overseer Locations

Once you've got the portable map sorted, you'll want to tackle the fast travel system, which runs on Overseer Pathways. This isn't your typical 'warp from anywhere' deal because you need to find and repair 16 Torn Overseers scattered across regions like the Dwellings, City Gates, and Nexus to connect Attunement Gates. The annoying limitation is that you can only initiate fast travel at Overseers themselves, so you can't just teleport from the pause menu. But here's the pro tip: prioritize unlocking the portable map first, which makes hunting down Overseers way less painful and drastically reduces backtracking while you're building your network.

All Boss Locations & Navigation Tips

Here's the good news: MIO has 18 bosses and none of them are missable, so you can hunt them down even after the credits roll. The first one, Egis - Worn Out Sentinel, shows up early as a combat tutorial, but later bosses get way trickier to find. Crow - Automated Reaper is a perfect example: you need the Hairpin ability to climb to the top of its area, then go through a hole in the left wall. SAWLONG requires the Slingshot skill to reach a spot beyond the giant book on the right side. Some bosses need specific key items, like Friends :) which won't even appear until you grab the Friendly Invitation. Others have bizarre entry methods: Calderon - Unyielding Furnace hides behind a fake container that you'll fall straight through into the arena, while Atmos - Weather Control Unit needs you to jump into a hole with strong wind next to an elevator. Ancile & Targa become accessible after you connect the map's right and left sides via a hole near the lift room. Then there's Debby, who only appears after you activate all water pumps in the Vaults, which opens a pipe leading to the boss door. For the true ending, you'll face Shii as the final boss after meeting specific progression requirements.

Advanced Boss Strategy Tips

General Advanced Strategies

The first thing you need to internalize is the white flash telegraph system. Every boss in MIO gives you a warning before their big moves, and these aren't subtle hints - they're glaring visual and audio cues like weapon flashes, screen-wide pulses, or distinct sound changes. Missing these means you're eating damage you could've avoided, so training your eyes and ears to catch them is non-negotiable.

Once you spot a flash, don't panic-dodge immediately. The sweet spot is dodging at the last possible moment, which gives you the longest invulnerability window and positions you for a counterattack. After the dodge, that's your cue to Hairpin in, land two or three hits, then immediately disengage. This rhythm - dodge, punish, retreat - is the backbone of controlling fight pace, and it keeps you from getting greedy when the boss is vulnerable.

Here's the mindset shift that'll save you hours: treat phase one as a classroom, not a DPS race. Your only job in the opening minutes is staying alive while you map out the attack patterns. Don't worry about your damage meter; worry about recognizing the tells. This patient approach pays off when phases change and patterns shift, because you'll spot the new telegraphs immediately instead of getting blindsided.

The Allocation Matrix is where you turn that knowledge into power. After you've learned a boss's rhythm, you can customize your loadout to exploit their weaknesses. If you're up against a high-damage bruiser like Ati, you'll want defensive abilities that give you more room for error. But if the boss has long vulnerable windows, you can stack offensive mods and turn those openings into huge damage spikes.

For the final boss Ati specifically, the community has settled on two effective modifier loadouts. On the offensive side, Glitch Trail, Afterimage, and Kinetic Thrust turn your brief attack windows into serious punishment. If you're struggling to survive, swap to Enhanced Dodge, Protective Overlay, and Self-Awareness - these give you the extra survivability to learn the fight without constantly returning to the checkpoint. The key is matching your matrix to the boss's tempo, not forcing one build into every encounter.

Rewards & Progression Guide

Boss fights in MIO aren't just about survival - they're your primary source of new toys. Every major encounter drops something that either cracks the world open or fundamentally changes how you play. Here's what you're actually getting for your trouble.

Boss Rewards & Unlockable Abilities

Boss	Reward	What It Does For You
Egis - Worn Out Sentinel	Silo Access Badge	Opens the Silo and other locked doors you've been walking past
Flora - Sentient Pearltrap	Aviaries Passepartout + Dodge	Unlocks the Aviaries zone and gives you a proper evasive roll
Crow - Automated Reaper	Harvester ability	Boosts your melee damage and makes clearing mobs way faster
Nabuu - Keeper of the Breath	The Breath (Pearl Fragment)	One of four fragments you absolutely need for the True Ending
Sol and Vin	Black Widow modifier	Stackable stat boost; also where you'll really need that Hairpin ability to stay airborne
Calderon - Unyielding Furnace	Progress Item	Story advancement that unlocks new zones automatically
Atmos - Weather Control Unit	Progress Item + Sail ability	Unlocks story zones and lets you glide through the air to dodge projectiles
Anra and Dr Halyn	Progress Item	Grants access to the Lab section

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Here's where things get interesting. The Silo Access Badge from Egis is your first real key, and you'll feel its impact immediately - every locked door on your map suddenly becomes a possibility. Flora's Aviaries Passepartout does the same for the sky zones, but the real prize is the Dodge ability it bundles in, which means you can finally stop tanking every hit like a chump.

Combat abilities are game-changers. Harvester from Crow makes your melee swings hit harder and faster, and you'll wonder how you ever cleared rooms without it. The Sail ability from Atmos (grabbed via a Strange Tube after the fight) is even bigger - it lets you ride air currents and completely ignore certain boss mechanics, but you won't get it until you're already pretty deep into the story.

Then there's the Pearl fragments. Nabuu drops The Breath, which is one piece of a four-part puzzle - you'll need The Blood, The Eye, The Breath, and The Hand to even challenge the True Ending boss. None of this is explained upfront, so if you're chasing the real finale, you can't afford to miss a single one.

Black Widow from Sol and Vin is a nice bonus, but that fight is also where you'll need the Hairpin movement ability to stay airborne, so make sure you've grabbed that tool from earlier zones. Progress items from Calderon, Atmos, and Anra/Dr Halyn are pure story keys - they're not flashy, but they quietly unlock entire sections of the map and keep your run moving forward.

The Keeper of the Heart is your baseline completion trigger; beat it and the credits roll. But if you want the actual ending, you'll be back to collect those Pearl fragments, which means re-clearing a fogged map in NG+ to find what you missed.

Conclusion

Mastering MIO's bosses is a journey of unlocking the Vessel's secrets, one key ability and story fragment at a time. From the essential Dodge and Sail to the Pearl fragments required for the true ending, each victory reshapes your capabilities. Equip the right modifiers, learn the telegraphs, and you'll be ready to face even the post-credits secret boss.