Alphys Undertale Guide

Alphys Undertale Guide

Of all the monsters you’ll encounter in your journey through Undertale, one of the most unique is the royal scientist, Alphys. As soon as you meet her, you’ll notice she has no interest in capturing or killing you, unlike most of the other monsters you’ve met on your journey.

She’s a strange, lizard-like nerd who has been monitoring you this whole time and comes off as charming and slightly overbearing. There are a few sides to her besides what you can see based on your first encounter, and this Alphys Undertale guide is all about getting to know her.

Bottom Line Up Front

Alphys is the royal scientist and has a crush on multiple characters in the game, namely Undyne. However, she helps you throughout your journey with no bad intentions, despite that help not always being required or wanted.

What is Alphys?

Alphys Undertale yellow reptile
Image from Fandom

A yellow reptile with a hunchback and a lab coat, Alphys is the royal scientist proceeding W. D. Gaster. She is mainly in charge of making technology and monitoring the underground. Her only other outfit is a dress a friend picked for her.

You’ll first find her at her lab in Hotland, where you can find her computer monitors recording your every movement. Seeing she’s been watching you might be scary, but she’s completely harmless. Even in a genocide route, she’d hide with other monsters away from you, and you never encounter her.

Who is Alphys?

Alphys Undertale
Image from Fandom

The shy, loner type who tends to lock herself away in her lab whenever she gets the chance, Alphys is often anxious upon talking to anyone in the game, including you. As a result, she frequently stutters, sweats, or makes self-loathing comments on herself.

Alongside her outward appearance and personality, she’s brilliant, creating robots using metal and magic and making many technological advances in the modern-day underground. She also loves anime and sometimes writes guides for video games. (Hah, imagine doing that!)

She created Mettaton’s body and conducted experiments using Determination. She also often crushes on half the characters in this game, including (but not limited to) Undyne, Asgore, and Toriel. She also does handy things, such as upgrading your cellphone or turning off lasers for you.

Undertale Alphys Normal
Image from Fandom

Many fans misinterpret her strong preference towards Undyne as being a lesbian, but it’s far more likely she’s supposed to be bisexual. She’s shown to have a thing for Asgore and just likes muscular men and strong women in general, especially in Deltarune.

Overall, she’s a sweet and caring character, always trying to help the protagonist despite messing up and causing problems on accident quite a few times. Her intentions are never wrong, and she’s always doing her best, even if her best varies from making a human-killing robot to giving you a sweet jetpack.

Relationships With Other Characters

Alphys manages to be one of the most well-acquainted of any Undertale characters. Despite her personality implying she’s an antisocial shut-in, she has met and engaged with most of the main cast and has some unique relations with a few of them.



You might expect her to be quite proud of Mettaton, her own creation, but it happens to be quite the opposite. Alphys is quite a fan of yours but accidentally made Mettaton out for human blood. After a quiz show containing quite the embarrassment for Alphys, you can see she has a bit of disdain for him in his current state.

After a ton of exciting television programming featuring Mettaton, with you barely getting away due to Alphys’ inventions, we eventually fight him. However, whether you decide to kill or spare him, Alphys shows obvious concern and worry about him, indicating she did care about him all along.

Mettaton used to be just a ghost and made a human fan club that Alphys was the only other member of. They got along quite well, and Alphys decided to make a body for him out of metal and magic, leading to the Mettaton we see in the game. However, even though she always enjoyed Mettaton’s presence, she worried he’d get too popular and forget about her.


Asgore Undertale

To sum it up quickly, Asgore is Alphys’ boss and also a bit of a more subdued love interest for her. She lies to him about her experiments with Determination but still tries earnestly to do whatever he asks. Their relationship is more or less business, but she seems to have a decently strong crush on him.

In the quiz show with Mettaton, answering Asgore to the question, “Who does Alphys have a crush on?” results in her getting extremely flustered and covering her face. In the game’s epilogue, you can talk to her, and she’ll refer to Asgore as “Mr. Dreamy,” which is not highly subtle. Her crush on him is more subdued than someone else but still noticeable.


Undyne Alphys Undertale

The most definite connection of Alphys’ is certainly Undyne. She spends time with her at her lab, having met her during her time in Waterfall; she quickly falls in love with Undyne but is always too embarrassed to say her feelings. She also made many of the puzzles in Waterfall, which is probably why those flower puzzles were so dang hard.

Her crush on Undyne is another Mettaton quiz show answer that gets her flustered, and she’s been shown to read comics with her, watch anime with her, write her name in her notes, name programming variables after her, and write fanfictions about them living together. So it’s pretty apparent she’s obsessed with her.

If you go down the route of a true pacifist, after a jokey date with Alphys, Undyne eventually enters, and after promptly dunking her into a garbage can, they agree to start dating. You can even see this in action during the true ending, where Undyne kisses Alphys on the cheek, making her incredibly flustered. A power couple if I’ve ever seen it.


Papyrus Alphys Undertale

Alphys’ relationship with Papyrus is one you see early on in Hotland, but it’s not really all too detailed. She mostly just posts on the same forum or blog as him, exchanging photos of her saying she’s a garbage can and Papyrus saying he’s a skeleton with sunglasses, muscles, and muscles that have sunglasses.

I would have loved to see more of these two polar opposite nerds, but their interactions are fun.



Although there isn’t much about this relationship, it’s still quite the fun dynamic. As soon as Toriel comes back into power, she fires Alphys immediately. However, this doesn’t stop Alphys from developing a crush on her quite quickly, and she ships her and Asgore. I guess big and strong people are just Alphys’ type.

Bratty and Catty

Alphys used to live on the street with these two and was like an older sister to them, taking them to the garbage dump to scavenge around and find goodies. However, after Alphys made Mettaton and impressed Asgore, she locked herself away in her lab and hasn’t interacted with these two since.

The Bad Endings

While each ending of Undertale is canon in its own way, every ending has something different, especially in how Alphys reacts and responds to the situation. It’s interesting seeing her specifically since Undyne was the last real line of defense to Asgore; Alphys acts as the plan B if you decide to go on a killing spree.

Genocide Route

You never see Alphys in the genocide route because she’s busy evacuating every monster she can find in Hotland to her True Lab and is defending what little of the underground you leave in your wake. So it’s pretty disturbing not to see her and to walk through the lab without encountering anyone.

Neutral Routes

If you decide to kill either of the people most important to Alphys on a neutral route, either Mettaton or Undyne, she disappears entirely. She is implied to have been so emotionally wounded by losing the loved ones that she didn’t want to live anymore. While there is no way to fight Alphys in the game, this route implies you can (if indirectly) kill her, and that’s just making me sad.

The True Ending

The True Ending Undertale Alphys

We get a ton more information on Alphys and the things she’s been hiding and been up to ever since she started experimenting with Determination when we go for the True Pacifist ending. But, to even begin this ending, our first destination will be Alphys’ lab, where we’ll find some horrendous things.

The True Lab

True Lab Location

After defeating Flowey and not killing a single monster, you enter Alphys’ “bathroom” and find the True Lab entrance. Here you learn about her experiments with Determination and the human souls, taking the near-dead relatives of other monsters and injecting them with Determination, turning them into horrifying monsters.

The monsters fused into masses of near-unrecognizable Almagamate creatures that all seem intimidating initially but are usually just lonely and want a friend. Eventually, after learning all of this, Alphys will feed all of them and explain exactly what she did.

After The Lab

Alphys After The Lab
Image By Monica Phillips

Before your horrifying delve into the lab that Alphys had hidden, you’ll have Alphys go on a date with Undyne, and then she almost gets to kiss her during the sequence with everyone in New Home after your lab excursion. But, unfortunately, Flowey will ensnare her along with the rest, and you’ll have to save her from her previous ways and reassure her that she can be confident.

She tells Asgore and Toriel about the experiments, which is when she promptly gets fired for the blunder. She talks about her hopes to watch anime on the surface and has released all the Almagamates to their families, so even in their horror; they can still be with the people they love. She gets a kiss from Undyne, and all is well.


Alphys Deltarune
Image from Fandom

So far, Alphys has appeared as mostly a minor character in Deltarune. Still, there is room for theory-crafting on what role she may play later in the story and acknowledging what role she currently plays and how that might affect things moving forward. Also, of course, Deltarune is still in development, so we may get more Alphys character-building later.


She’s mostly the same old Alphys, but with a few things changed. Namely, she’s a school teacher instead of a scientist. It’s implied she’s still pretty intelligent and capable of learning quite a bit, but not necessarily in a science or technology way.

She went on quite a bit in Undertale about how “Mew Mew Kissy Cutie 2” was a butchering of a beloved franchise and how much she hated it. Still, in Deltarune, she never stops talking about how much she loves the sequel compared to the original and how people who prefer the first are wrong.


Her computer wallpaper is an overly muscular superhero, so it’s implied she could still have a crush on Undyne. Still, if you ask Undyne about Alphys, she has no clue who you’re talking about. They haven’t met, but Alphys would probably still crush on her if they did.

She still knows Asgore and is friends with him. She occasionally gets flowers from him, loans him comics, and watches anime with him. She says Asgore is like a superhero to her, implying that, once again, she might be crushing on him.


Overall, she’s still quite the nerd, and we get a bit of minor storytelling with her leaving milk out for a cat every night, despite never seeing the cat. There are many creatures and characters we could assume to be taking the milk, namely Susie or Catty, and this detail could either become a central plot point or a recurring joke. You never really know with Toby Fox.

I think we’ll, at the very least, see the start of an Alphys and Undyne relationship bloom again, if not get to see the entire thing play out this time. I also think Alphys may become a significant story character, there’s just a decent amount of focus given to her over other Undertale veterans, and it would be fun getting to see her as a party member or just seeing her in the dark world at all.

Questions and Answers

Question: Is Alphys gay in Undertale?

Answer: Though many assume Alphys is a lesbian, she shows several times through the game to crush on men and women, implying she’s bisexual.

Question: How do you fight Alphys in Undertale?

Answer: No matter what route you take in Undertale, you can never fight Alphys. She befriends you immediately on Pacifist, disappears on neutral, and hides away on genocide.

Question: How do you go on a date with Alphys?

Answer: You’ll eventually go on a date with her throughout the story by playing through the game without killing a single monster. This leads to her dating Undyne, so don’t get your hopes up.


Alphys has always been one of my favorite characters in Undertale, whether it be for representation or just because I enjoy almost every single scene she’s in and end up wanting more content with this funny, nerdy reptile that’s always embarrassed about every single thing she does.

I really hope we get more time to spend with Alphys in Deltarune. Currently, she’s really only been a school teacher who sometimes comments on our poor attention and sleeping habits. It would be fun to interact more with her and Toriel, see her relationship with Undyne come about all over again, and hang out with her more.

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