Part Five: King Asgore

Main Walkthrough

Undertale is a game of choices, and the most positive choice you can possibly make is to not harm anyone. Thanks to the game’s unique combat system, it’s entirely possible for you to do this, too, progressing throughout the Underworld without killing a single random enemy or boss monster. The Pacifist route is the choice to make if you want the ‘true’ ending of Undertale…

… but it’s not easy. Because you aren’t killing monsters, you don’t gain experience, and because you don’t gain experience you don’t gain levels, and because you don’t gain levels it’s really really hard to survive the later parts of the game. Still, it can be done, and the ultimate reward is satisfying.

Once it’s established that you’re on a Pacifist run, Undertale will change, and you’ll run into different situations that set it apart from a Neutral run. If at any point you kill an enemy, you’ll be thrown into a Neutral run. Don’t save if this happens or you’ll have to reset. 

It is worth noting now that you have to complete the game on a Neutral run at least once before you can do a ‘true’ Pacifist run. If you attempt a Pacifist run on your first go through the game it will force you into the Neutral path right at the end, because some of the things you need to do to complete Pacifist are only available once you’ve completed Neutral. You do not need to completely restart your game, however! Just reload your save after fighting Asgore, and, assuming you've fulfilled the requirements below, you can head out of the Core to proceed into the final stages of the Pacifist run.

I highly, highly recommend you complete a Pacifist run before a Genocide run. It provides the happy ending you want… but the Genocide run will ruin it. Just putting that out there now.

The Ruins

The Ruins aren’t much different from normal until you reach the end. Just… don’t kill anything. You can Spare pretty much everything in the Ruins from the start, though you won’t get any gold unless you perform the following actions first:
  • Froggit - Compliment
  • Whimsun - Terrorize
  • Moldsmal - Imitate
  • Migosp - Get rid of every other monster
  • Loox - Don’t Pick On
You’ll face two bosses down here. The first, Napstablook, is easily defeated just by Cheering him until he goes away. The second, Toriel, can be defeated in the same way, using Spare over and over - but it will take a fair bit longer for her to give in. She will not kill you unless you’re really determined to die, however.

(Technically you'll also face the unique Dummy enemy as your first foe. You can 'kill' it if you want and not take any heat.)

I highly recommend you buy either a Spider Donut or a Spider Cider from the bake sale in the Ruins before you leave, and keep it safely in your inventory. It will allow you to skip a boss who is fairly tough for Pacifist players.


Same deal here as on the Neutral path, at least for the majority of the section. The battles get a bit harder here, ‘cause your lack of level progression becomes increasingly dangerous to your survival. Stock up on healing items and get the latest armour whenever possible. 

You can mercifully defeat enemies in Snowdin with the following actions:
  • Snowdrake - Stall one turn until it tells a joke, Laugh
  • Icecap - Ignore x2, Steal
  • Doggo - Pet
  • Lesser Dog - Pet
  • Gyftrot - Undecorate x3
  • Jerry - Ditch once every other monster is gone
There are a number of bosses in Snowdin. First up are the Dogi; Roll Around, Re-Sniff, and then Pet both of the dogs. Second is the Greater Dog; either Beckon, Pet, Play, and continue Petting, or Ignore the Greater Dog until it goes away. (The results of Playing and Petting are more adorable.) 

The last boss is Papyrus, whom you simply have to battle until he agrees to Spare you. You can also win a date with Papyrus if you Flirt with him during the battle, which I recommend for lulz. Make sure to befriend him after fighting by speaking with him at his home.


More dodging. The enemies are harder and you still have the same amount of health, so finding the Old Tutu (behind the first waterfall) is wise for your long-term survival. I also highly recommend getting the Torn Notebook from the turtle vendor, as it will extend the amount of invincibility time you receive whenever you get hit. (And you can hold on to it, because if you’re doing Pacifist right, you should neeeever need to attack anything. 

You can mercifully defeat enemies in Waterfall with the following actions:
  • Aaron - Hit him until he has low health, Flex
  • Woshua - Clean, must touch the green suds
  • Shyren - Hum
  • Molbyggs - Unhug
  • Temmie - Flex
There are two bosses in Waterfall. The first is the Mad Puppet, which you can’t really Spare - you just have to wait it out until Napstablook shows up. Guide shots from the dummies into it.

The second is Undyne, and she’s quite the toughie in this mode. (You’ll know you’re still on Pacifist if she acts like an over-dramatic nutter before the fight begins.) You need to consistently avoid her dart attacks while not hurting her, which can take a long time. Get a few healing items and have the Torn Notebook equipped to make this an easier process. 

Once Undyne starts repeating ellipses (…) over and over, you can flee the fight. Keep running into Hotland - she’ll pursue, but you can immediately flee - until she collapses, then give her some water from the water cooler. Once she leaves, head to her house (it’s near the snail farm and Napstablook’s home) and you will engage in some ‘friendship’ with her and Papyrus. Intense. Make sure you do this! 

One final note: When you first enter Waterfall you'll find Sans sitting at a guard post. Speak to him and he'll ask if you want to 'hang out'. Say yes. You need to do this to complete the route.

Undyne is serious about her culinary pursuits.

The game’s final area is particularly dangerous. The enemies here are at their strongest, and you still have twenty health. Eesh. Watch their patterns carefully, and always carry restorative items. On-screen obstacles are particularly dangerous at this point, so be careful whenever Mettaton shows up to mess with you.

You can mercifully defeat enemies in Hotland with the following actions:
  • Vulkin - Hug
  • Tsunderplane - Approach, Flirt
  • Pyrope - Heat Up x2
  • Madjick - Stare at both orbs
  • Knight Knight - Sing x2
  • Astigmatism - Don’t Pick On
There are three bosses to overcome in Hotland. The first are the Royal Guards; you can stop them by Cleaning 02’s Armor, then Whispering to 01. Second is Muffet, whom you simply have to outlast - unless you use a Spider Donut or a Spider Cider, which will send Muffet straight to Mercy mode. Hopefully you saved one or the other from the spider bake sale back in the Ruins. The last is Mettaton EX; to best him you need to get your Ratings above 10,000. Posing, taking damage, and using branded items (like a Glamburger) will raise this number nicely during the fight.

While wandering through Hotland you'll find Sans, in one case out front of the MTT Resort. He will again ask if you want to hang out. Say yes. This must be done to continue on this route.

At the end of the Core - and after a simply lovely visit with Sans - you’ll have to fight Asgore. He is exactly the same as he was on the Neutral path, but now you have significantly less health. The same tactics apply as before. I highly recommend you save the Butterscotch Pie from the beginning of the game for this fight, as using it will reduce Asgore’s strength and defence for the entire battle. You’ll need the extra help.

Once Asgore is defeated, choose Mercy. Unlike on the Neutral path, this is not a useless gesture, and will not lead you into a battle against Flowey. You are, instead, taken to the ending - and when you reload your save, just before Asgore, you can leave the Core to unlock the rest of the game. We’ve got some more stuff to do, and it’ll take you to a brand new area. Didn’t see that one coming.

(If the following events are not unlocked then you didn't befriend someone. You need to hang out with Papyrus and Undyne at their respective houses before you can unlock the remainder of the Pacifist run.)

Alphys is intense. INTENSE.
True Lab

- Return to the Core. It’s now open, and you can explore the Underworld again. Exit and cross the bridge from the Core to the MTT Resort. Along the way you’ll get a phone call from Undyne; follow her directions and head over to Snowdin via the boat man.

- Undyne is out front of Papyrus’ house. Talk to her and she’ll give you Undyne’s Letter. Take it to Alphys’ Lab in Hotland and use it on the front door to ENGAGE DATING. This will last a while, but it’s hilarious.

- You’ll wind up in Waterfall. Wander back to the boat man and return to Hotland, then into the Lab. There’s a note sitting on the floor in front of the washroom, because, of course, it’s not really a washroom. Head inside.

- There are a number of computer terminals along the walls in here. Read them at your leisure. Once the music starts up, check to your left for the continued path, a save point, and a vending machine that dispenses Popato Chisps for 25 gold apiece. A door here refuses to open; ignore it for the moment.

- Head west. There’s a small kitchen ahead, with three sinks on your left. If you check the furthest sink three Memoryheads will appear. These mystery creatures will create ghastly faces in your box; stay near the edges, and mostly still, to avoid ‘em. Cell the Memoryheads, then Refuse one of them to get a Spare win. They’ll leave behind a Red Key. Use it on the panel in the room leading off of the kitchen.

- Return to the room with the vending machine. The door on the right is now open. It leads to a room full of beds. The one nearest the entrance can be slept in, though the resulting experience is… creepy. The third bed in the middle row has a hidden Yellow Key to grab. There’s a save point in the corner; use it, then enter the northern door.

- The path splits. Take a right and you’ll find a room full of fans. Turn them on to summon a beast called the Amalgamate, which appears to be teeming with dogs. It likes homing attacks; no big deal. Bizzare. Beckon it, then Pet, then Play, then Pet it twice more to appease the beast. Take a left and you’ll find a door leading to a creepy shower stall, within which is a Green Key.

- Continue west from the shower room. In the next area is a save point, but it’s actually a monster named Lemonbread. Its chomping attacks are bizarre, but you can end the fight quickly with Flex. In the northeast of this room is the lock for the yellow key, as well as a bunch of highly relevant VHS tapes; to the west is a room full of fridges. When you try to enter the room in the far west you’ll be attacked by another Amalgamate; stop this poor creature by Joking three times. It will drop the Blue Key. The Green Key gets used on the slot in the door.

- Backtrack to the room with the beds. Down the right hall from the beds is a series of mirrors. You’ll get attacked by a Reaper Bird; Mystify works against the thing. Watch out for those butterflies. The door at the end of the hall contains the slot for the Blue Key.

- Return to the entrance. Assuming you dealt with all of the slots, the door in here will now be open.  Be sure you’re ready for this, because even though this place is not the game’s final destination, it does shunt you there pretty quickly. You know where to go from there.

Asriel, the big bad of Undertale.
He's just misunderstood, I swear.
Asriel Dreemurr

Hoo boy. Psychedelic. Asriel is one hell of an opponent, but you have a few distinct advantages in this fight. First, even if you die, you’ll immediately come back to life, and in roughly the same spot in the fight. So, you know, that makes it easy-ish. Second, if you use the Action menu you’ll find the items ‘Hope’ and ‘Dream’. Hope reduces the amount of damage you take on one round, while Dream fills your inventory with LastDreams. These items restore 17 points of health. Sweet. And, third, Asriel always telegraphs his attacks before using them, so you know what’s coming. You won’t need this too much, but it’s still cool.
  • GALACTA BLAZING. He rains stars down upon you. This starts as a diagonal spray, then turns into large loops. It looks crazy, but the stairs are slow and relatively easy to avoid.
  • CHAOS SLICER. He slashes at you with a pair of swords. Follow his movements to figure out which side of the box he’s attacking. His final attack will hit both sides; head for the middle, then slide away once the sparks from the attack appear.
  • CHAOS BLASTER. He targets you with a cannon. There are tracer lines from the cannon that you can follow at first, but eventually it gets so fast that you’re better off just moving back and forth horizontally every second or two. Move on the first blast; stay still on the second; continue until he’s done. He follows this up with a huge laser blast, but it’s easy to avoid. Later in the fight the cannon will unleash a huge star field after firing the laser; avoid it by staying close to the bottom of the box.
  • SHOCKER BREAKER. He targets you with lightning blasts. Exclamation boxes mark where they’re going to hit; get out of the way.
  • HYPER GONER. This is Asriel’s last attack, and despite how flashy it is, you just need to avoid the debris sliding towards the centre of the giant skull.
Easy enough fight. You can’t hit Asriel and you can’t Spare him, so just hold on and survive. You can die as many times as you like, but the fight will go faster if you don’t. Simple enough.

Once Hyper Goner goes off Asriel will shift forms. From this point on it’s a simple matter of releasing hostages and shedding all of the tears. Enjoy!


Considering this game was clearly inspired by Earthbound, it should be no surprise that you can wander around after the final battle. Every single person (except maybe one) has new dialogue, including the vendors, and there are many new NPCs - most of them monsters outside of Snowdin - who have things to say. It’s also worth it to talk to the familiar faces until they run out of dialogue options, and to keep using your Cell Phone until it’s obviously time to stop. You’ll get a new message with each new room you enter. It won’t last forever, but there are nevertheless a lot of messages.

This begs an interesting question: are the Ruins open? Short answer: yes. And, yes, it is absolutely worth it to walk through them to the very beginning of the game, assuming you’re invested in the story. Just keep in mind that you need to walk aaaaaaall the way back to the final room once you’re done looking around. It’s a long trip…. but the NPC sitting beside the flower bed where you dropped in is so worth it.

Almost done. First there are credits. There are extra credits. The extra credits, or, more accurately, the Special Thanks, will fly at you. If you manage to avoid them all, which is impressive in and of itself, you will unlock a secret door in Snowdin, near the last of the X and O puzzles. There is a developer’s room inside. It is silly. Huzzah!

One last thing, after all the sweetness and sunshine. When you return to the main menu you’ll find a slightly different option, allowing you a ‘True Reset’. A True Reset wipes out virtually every decision you’ve previously made. As a consequence, you won’t see characters reacting to your previous games anymore. It’s a clean slate in almost every sense of the term. The ‘almost’ only really comes into play when you do the complete opposite of a Pacifist run…

… and that’s a Genocide run.

Main Walkthrough