Alphys
Dr. Alphys is a major character in Undertale.
Though she does not make an actual appearance until halfway through the game, Alphys has played a significant role in the game's story and the player can find hints of how involved she is in the happenings of the Underground.
Throughout the Snowdin region, the player can find various trees, bushes and snow piles that contain hidden cameras. And when the player reaches the Colored Tile Maze puzzle, Papyrus will state that it was devised by Alphys herself. But it's not until the player gets closer to Hotland that they start getting a clearer picture as to who Alphys is, with the player's choice of taking the Genocide or Pacifist route affecting how much of Alphys they will find out.
If the player is taking the Genocide route, they will hear about Alphys from other characters but will never actually see her. During the Undyne the Undying boss fight when the player finally defeats her, Undyne will state that Alphys was watching over the fight at the ready to evacuate everyone and alert Asgore in the event something went wrong. When the player arrives at the Laboratory, Mettaton will be there to greet them and say that Alphys isn't around as she's been busy evacuating the rest of the Underground. Mettaton will then claim that Alphys really is the smart one for choosing not to fight someone like the player. Reaching the MTT Resort, the player can go to Bratty and Catty's alley out back to read the notes they left before evacuating. The notes say that Alphys personally came to help Bratty and Catty evacuate, but she made a fuss over the fact that the two wanted to use up their gel pens to write the notes. The player won't hear anything more of Alphys throughout the rest of the Genocide route.
In the Pacifist route, the player will hear more of Alphys from Undyne before the start of her boss fight, with Undyne stating that Alphys' "history books" described humans as having "giant robots" and "flowery swordswomen." And while trying to escape from Undyne, she'll state that it was Alphys who told her about humans' Determination.
When the player arrives in Hotland, they will have to enter through the Laboratory if they are to progress any further and it is there that they will finally meet Dr. Alphys. Emerging from what appears to be a bathroom, Alphys will immediately panic a little from not expecting you so soon saying that she hasn't been able to shower or clean up. Calming down, Alphys will formally introduce herself as Asgore's royal scientist but she's not looking to stop you like everyone else. She will followup on that by saying that she's been observing you since you left the Ruins via hidden cameras, and ended up wanting to help you after seeing you befriend so many of the Underground's residents. She'll say that she can help you get to Asgore's castle without issue, but there's just one problem; she built the robot Mettaton for show business but recently added anti-human combat features for the event that a human falls into the Underground again. Once Alphys started supporting you, however, she sought to remove those features only to make Mettaton into a robot that makes a sport out of killing humans. As soon as Alphys says that Mettaton might not show up, the robot in question will burst through the wall and begin a quiz show meant to kill the player. Throughout the quiz show Alphys will stand off to the side, secretly providing the player answers to the questions. This will go on until Mettaton brings up a question regarding a dating simulation game that just so happens to be Alphys' favorite, and not only does she blurt out the answer but Alphys will also go on to explain how significant it is to the game's story. Realizing that Alphys has been helping out the player, Mettaton will instead bring up the question "Who does Dr. Alphys have a crush on?". This question reveals that Alphys has a huge crush on Undyne, with Mettaton elaborating that Alphys writes Undyne's name in the margin of her notes, names programing variables after Undyne and even writes stories about the two of them living together. Once Mettaton leaves, the player can speak to Alphys and hear her say Mettaton wasn't supposed to ask that last question, hinting at what Mettaton is really doing. Just as the player is about to leave the Laboratory, Alphys will offer to give them her phone number to remain in contact only to see how old the player's phone is. In response, Alphys will upgrade your phone to give it texting capabilities, a key chain, more storage space for your items and even internet access so the player can have access to the Underground's social network. After an awkward silence, Alphys will then excuse herself to the "bathroom" and the player is free to either leave or look around the Laboratory some more.
Taking the escalator to the second floor of the Laboratory, the player can see what Alphys' most recent "research" consists of and a few hints of her past. Right away the player will come across bookshelves of "research materials." One shelf consists of scientific books, but the dust on them may indicate that they haven't been looked at in a long while. All the other shelves consist of books, VHS tapes and DVDs labeled as "human history", but a closer look at them will reveal that they are all comics and cartoons that don't strike the player as being very accurate. Next to a strange machine by the shelves, the player can find Alphys' work table which has plans concerning her past work laid out but the dust covering it all may again indicate that she hasn't used it in a long time.
As soon as the player leaves the Laboratory, their upgraded phone will ring to alert them of "status updates" on Alphys' social media page regarding how she didn't actually watch the fight between Undyne and the player, but that she'll ask about it later. As the player navigates through the Magma Chamber, they will be alerted to more "status updates" about how Alphys will call the player to help them through Hotland but hates talking on the phone. After updating that she's had her claw over the last digit for five minutes, Alphys will attempt to call the player directly only to hangup before they can answer. When Alphys finally calls, she will let you know how the security lasers ahead work and immediately hang up from being so nervous. Alphys will continue to alternate between posting on social media and calling the player as they progress through the Magma Chamber. When the player encounters Mettaton during his cooking show, Alphys will stop Mettaton just as he's about to kill the player and then alert them to the "jetpack" feature on the phone to overcome the timed minigame. When the Core comes into view, Alphys will call to explain that that is your destination as it has an elevator that leads straight to Asgore's castle.
After some more "updates" and assists from Alphys, the player will find themselves in a darkened room with Alphys calling in to say that she'll hack into the system to lighten up the place. Finding themselves on "MTT News" and that everything to "report" is in fact a bomb, Alphys will let the player know that their phone also has a bomb-defusing program on it and explains how to use it. Once all the bombs have been defused, Mettaton will announce that the big bomb will explode in 2 seconds only for it to not do so. Alphys will then call in to say that she deactivated it while Mettaton was "monologuing" and then tell the player that she's starting to get more confidant about helping you out. When the Core comes into view again, Alphys will call again to talk about how quiet you've been. Wondering if it's because you're nervous about meeting Asgore, Alphys will assure you not to worry since he's a "nice guy" and that you can make it through the Barrier with the power of your Soul.
While the player is working on the next set of puzzles, Alphys will call to ask if you would be interested in watching a human TV series with her sometime. The show is the anime adaptation of her favorite dating sim game, and excitedly goes on to explain the premise of the show and the main character. Realizing that she is pretty much spoiling the whole show, Alphys will again say that she would like to watch it with you once you reach the end of your journey and then hang up.
When Mettaton presents the player with the Colored Tile Maze puzzle, Alphys will hack into the system to save you from the extra dangers that Mettaton added should you not finish it in time. However, Mettaton will remind everyone that one of the traps of the maze was that a Monster will come to fight when you step on the green tiles, and announce that he is the Monster to fight. When the fight starts, Alphys will call to tell you to press the yellow button on your cellphone as it is another new feature she added to help you. Pressing the button, the player can now shoot bullets at Mettaton to "defeat" him, although he won't seem all that impressed. Alphys will then call again to congratulate you on your victory, and then go on to explain that before meeting you she didn't like herself all that much. Before hand, Alphys felt like a "screw-up" who couldn't do anything without letting others down, but now she starting to feel more confident about herself after helping to guide you. Alphys will finish up by saying that the Core is just ahead past the MTT Resort.
At the Resort, the player can go to the back alley to the right of the building, where they can speak with Bratty and Catty to hear more about Alphys. According to the two friends, Alphys use to live on the same street as them and was like a older sister to them. The three of them would frequently go to the dump to look through the trash for anything that interested them, but when Alphys became the Royal Scientist Bratty and Catty didn't see her that often since then. The two will then go on to say that, back then, Alphys had a bit of a crush on King Asgore and it was likely that trying to impress him was one of the reasons that Alphys built Mettaton. But ever since then nobody has seen anymore of Alphys' work or of her, with Bratty and Catty passing it off as her just spending all of her time in the Lab. If the player is able to buy the Mystery Key from Bratty and Catty, and then open the red house back in the Waterfall area, they can read about how Alphys and Mettaton met. Back when he was still a ghost, Mettaton had started a Human Fanclub but Alphys ended up being the only other member. Mettaton described her as a dork who was "obsessed with awful cartoons" but found her funny enough to want to meet with her again. Eventually, Alphys came to Mettaton with sketches for a mechanical body that she wanted to make for him, a body that Mettaton described as being "beyond my wildest fantasies."
When the player starts working their way to the Core, they'll notice that there are already some people heading inside. Right away, Alphys will call to say that nobody else is supposed to be at the Core, but that's not something to worry about as the elevator is just ahead. However, once inside it will quickly become apparent that things are not going as Alphys said they would; the elevator doesn't work, the actual layout of the Core doesn't match up to Alphys' map, traps are set up in the opposite order Alphys anticipates, and there are several monsters ready to attack you. Alphys will try to keep calm and continue to help, but with each call she makes Alphys just gets even more flustered until she says she needs to figure it out. Once the player finally reaches the path to Asgore's castle, they will be confronted by Mettaton who will reveal the truth of the situation. Apparently when Alphys was watching you before arriving to Hotland, she didn't just want to support you she wanted to actually become a part of your "adventure." She reactivated the puzzles in Hotland, disabled the elevators and asked Mettaton to "act" like he had gone beserk, all so that she could help you out and become the "heroine" of your story. And now, according to Mettaton, this is to be Alphys' finest hour; waiting right outside the entryway, Alphys will come to interupt your battle with Mettaton to "deactivate" him for good and then convince you to stay in the Underground. However, Mettaton has had enough the "predictable charade" and started changing things up without Alphys knowing it, like the layout of the Core and all the Monsters attacking you. And now, as well as lock the door to the area, Mettaton will bring you high up on a platform to ensure that Alphys won't interupt the fight. During the fight, however, Alphys will be able to call you to tell you of a switch on Mettaton's back that should render him vulnerable, only to transform him into Mettaton EX. Once Mettaton's been beaten, Alphys will finally get the door unlocked and is shocked to see the state Mettaton is in. She'll calm down a little once she realizes that Mettaton simply ran out of battery power, but will ask you to go on ahead while she collects her thoughts. Catching up once the player nears the elevator, Alphys will admit that your human Soul isn't enough; to pass through the Barrier, one needs the power of a human Soul and a Monster Soul. She'll then apologize for lying to you about so much, then leaves.
In the Neutral Pacifist ending, Alphys will first be mentioned by Papyrus who will say that he's been helping with her research in finding an alternate means of leaving the Underground. Papyrus will also state that while Undyne's methods of helping with the research are rather destructive, Alphys does seem to enjoy having her around. When Undyne joins in on the call, she'll say that Alphys is pretty much the same as usual albiet a little more reclusive that before. But Undyne will assure that whatever is bothering Alphys, she'll be there to support her. Should the player have spared Flowey, he will appear after the phone call to question your actions. When Flowey states that he may know of a way to get a better ending, he'll suggest that you go visit Alphys again after loading up your Save File, saying that you may find "the key to your happiness" if you become better friends with her.
To fulfill the True Pacifist route, the player will have to Continue the game from their Save before Asgore's boss fight, and fulfill a request from Undyne regarding Alphys. To recieve the request, the player will have to leave the New Home and go to the entrance of The Core. There, the player will recieve a call from Undyne saying that she has something for you to deliver. Arriving at Snowdin to meet her at Papyrus' house, Undyne will give the player a letter that's addressed to Alphys, saying that she can't deliver it herself because she can't stand Hotland's temperatures and that she will kill you if you read the letter.
When the player delivers the letter to Alphys, it turns out that the letter was a means of asking Alphys out on a date but Undyne had neglected to sign her name, so Alphys initially thought that it was written by the player. Going to the dump for the date, the player and Alphys only just arrive when Alphys sees Undyne coming. She'll immediately hide behind a nearby trashcan just before Undyne arrives, asking the player for the letter so she can deliver it herself. Once Undyne leaves, Alphys explains that while she does really like Undyne she's scared that she will hate her once she knows the truth. When Alphys and the player rehearse a mock-date to prepare her, Undyne overhears Alphys shouting and thinks the two are on an actual date at first. After some stammering, Alphys finally admits most of the truth about herself to Undyne mainly about how her "research" was really just watching anime and reading comics. In response, Undyne says that while she isn't into "nerdy" things that much, she cares more about how passionate Alphys is for it all and is willing to train her to become confidant enough to not have to lie about herself to others. At this point, Papyrus steps in to do Alphys' training, leaving the player with Undyne who is now concerned about how "real" Alphys' anime and comics actually are.
The player will then have to follow Alphys back to her Laboratory to see for themselves what Alphys is hiding. Inside, the player will find the door to the "bathroom" wide open and a note lying on the floor infront of the door. In spite of the handwriting the player is able make out that while Alphys is grateful to everyone's support, there are still some things that only she can resolve on her own and she intends on doing just that. Alphys ended the note by saying that if she doesn't come back and everyone wants to know the real truth, then they should go through the door by the note. Entering the doorway, the player finds that it actually leads to an elevator, which quickly loses power and falls straight to the bottom. Surviving the fall, the player finds themself in the True Lab.
Throughout the True Lab, the player will find various files about the research Alphys conducted in the past and their end results. When she became the royal scientist, Alphys was tasked by Asgore to conduct research on Souls to figure out if it's possible to overcome the limits regarding Human and Monster Souls. Working with the research and equipment of the previous Royal Scientist, Alphys started conducting experiments on Monsters who had "fallen down" and upon the Human Souls Asgore currently had to see what could be done. Alphys soon discovered that the reason Human Souls last longer after death than Monster Souls is because they possess "Determination", and eventually found a way of extracting Determination. Alphys theorized that if she could insert Determination into a Monster's Soul, they it may allow them to last longer than normal after the Monster dies. When the monsters who had Determination inserted into them revived, Alphys was not sure of what to make of it since she couldn't extract their souls now yet she had already called their families saying that they'll come home alive. Unfortunately, it turned out that the composition of a Monster's body could only handle the power of Determination for so long, and eventually, the Monsters melted and fused together to become the Amalgamates the player encounters throughout the True Lab. Since Alphys had already called their families saying they would come back, she started to get very overwhelmed when people started calling to ask about what happened, contributing to her current social anxiety and reclusivness. After Alphys explains all this herself, the player can read some files regarding another aspect of her research; inserting a Soul into a soulless entity. The files state that Alphys had taken the first Golden Flower in Asgore's garden and managed to insert a Soul into it. But then the flower disappeared, presumably before Alphys could reveal it to Asgore.
When the player goes to confront Asgore again, Alphys will be the third of your friends to arrive to stop him from fighting you. Noticing Toriel, Alphys will think to herself "There's two of them?" apparently having been unaware that Asgore once had once been married. When Asgor starts feeling down from seeing how well Toriel gets along with Sans, Alphys will try to help Undyne cheer up Asgore only for Mettaton to come along and say that the two ladies should kiss. After Toriel states that you'd do just fine in the Underground with everyone, Alphys will point out that it was Papyrus who called everyone to tell them to come and ask him how he knew. When Papyrus says that "a little flower told me", Alphys will quickly piece together the implications of that only to be trapped by said flower along with everyone else. When Flowey tries to claim the player's Soul for more power, Alphys and the others were able to use some of their power to protect you until Flowey absorbed their souls and the souls of every Monster in the Underground, turning back into Asriel. During the battle against Asriel, he will taunt the player by saying that every time you "die" during the battle everyone's memories slowly fade away and they will eventually forget you altogether. When the player fails to recover their SAVE file, they decide to use that power to instead SAVE their friends. When the player goes to SAVE Alphys, she'll speak of how she thinks everyone hates her and that she should keep lying about herself to be accepted. But as the player takes actions that they have done before, like reasure her and ask about her favorite comics, Alphys will regain all of her memories.
After the Barrier is destroyed and Chara is fully purged from the player, Alphys will be among those who will await to go up to the Surface with Frisk. Once back on the Surface, Alphys will remark at how the scenery looks even better than what she's seen on TV or ever imagined. During the end credits, Alphys will be seen with Undyne at the beach playing a video game, only to be knocked unconcious by a kiss from Undyne.