Faust is an incredibly tall man who is usually seen wearing a green and purple shirt with purple and yellow striped pants and a lab coat. He also wears a thin black headband and usually has a straw in his mouth and a beaker in his hand.
Personality-wise Johannes seems to fit the typical mad scientist role, he has a passion for experimenting and in particular has a specialty in studying vampires. He has also been seen to have some amoral tendencies. He has no problems with breaking into and destroying other peoples property, as seen with him breaking into Mikuni's shop and melting the head of one of his dolls, and deceiving people (such as drugging Mahiru with tea). When speaking he comes off quite hyper and melodramatic at times.
Nothing is known about his background so far.
Johannes first appears in chapter 28 when Mahiru approaches Mikuni's shop. Before he can open the door, Johannes starts speaking to Mahiru, who he thinks is Mikuni. From the other side of the door, Johannes greets Mikuni and says he has something important to tell him. Johannes says he broke one of Mikuni's dolls because he keeps telling Mikuni not to leave his things where he can reach them. Johannes then pokes a headless doll through the crack of the door. He explains that her head popped clean off and that he made Mikuni a special juice by melting her head. He says that now Mikuni can be one with her body and soul. Johannes laughs while saying this and opening the door. He and Mahiru finally notice one another and ask who the other is.
In the shop, Mahiru asks about Mikuni and Johannes tells him that Mikuni is away from the shop more often than he is present. When asked if Mikuni is his friend, Johannes become disgusted and says that is gross.
Johannes then asks Mahiru if he is one of Mikuni and Doubt Doubt's subclass and Mahiru say no. Mahiru introduces himself. Johannes calls him by the wrong name and once Mahiru restates his identity, Johannes has a realization and rummages through a desk. He welcomes Mahiru to his laboratory and tells him to have a seat, calling him the wrong name again. Johannes announces it is time for an experiment and pours tea into a beaker for Mahiru. He tells Mahiru it's a welcome for the eve of sloth. Johannes gets Mahiru's name wrong again and says that he is no good at remembering names because there is no point. Johannes decides to write Mahiru' name on his forehead and laughs, stating that now he won't forget it.
Mahiru asks who Johannes is and he replies that he is a scientist, a researcher, an expert on vampires. He formally introduces himself and tells Mahiru he can call him by any name he wishes. He tells Mahiru that he is the one who made the anti-vampire water.
Johannes then get excited, grabbing at Mahiru, and asks him to let him touch, examine, and experiment on his vampire. Once he finds out Kuro is trapped in a ball, he is disappointed and surprised. He then begins crying, and cheering the limitless possibilities of the world. He asks time to freeze in that moment.
Johannes then grabs Mahiru and pushes him into his laboratory on the other side of a mirror.
On the other side, Mahiru asks Johannes if there is a cure for Kuro in the books he has. Johannes remarks that kids these days always ask others or the internet for answers. He states he wants to tells Mahiru to just read them, but that is too boring. Johannes tells Mahiru the answer is not in the books, as far as he knows.
Mahiru asks Johannes why he studies vampires. Johannes replies that he is sailing a ship, going against the flow of the river. He is going from downstream to higher upstream. He states that if you want the status quo, you stick with the flow. People can't stay in the same place forever and that they must always seek out new things. He becomes excited, saying that people must take the first step if they want to accomplish anything. He exclaims that satisfaction is stagnation, and that stagnation is death. He wants to know, see, experience, feel, and understand things. He says that even after mastering scientific fields, he still knows nothing. Johannes believes to not study a gift such as vampires is simply rude.
Johannes then begins to wonder how awesome the power of a servamp is. He reasons that sending them out to battle would assure victory for any country and that they are the ultimate weapon. He is thankful for Tsubaki making vampires fight each other, due to the progression of technology during wartime. He says that he cannot leave Sloth in a ball. he must turn him back.
Johannes then gives Mahiru tea, which he now drinks, and tells him he should not be so trusting. Mahiru become unconscious and falls to the floor. Johannes says that even though there is nothing in the books about Kuro's condition, it won't stop him. He announces that he is sending Mahiru inside Kuro using the only method.
Johannes becomes excited about being able to experiment on Sloth and is thankful for the moment. He asks time to stand still, but then retracts this statement because if time were to stop, he would not be able to experience that moment.
Johannes wishes Mahiru good luck and sends him off with a poem.
He later appears again in chapter 49 to experiment on Lawless, Licht, and Misono. He becomes extremely excited, yelling and crying because he has the chance to experiment on so many different truths.
Not much is known about their relationship yet, it's unknown how they met each other or what they're working on together. Despite being grossed out when asked if he was Mikuni's friend and Mikuni often yelling at Johannes, they seem to be quite friendly with each other. Mikuni is even seen complimenting Johannes for his capabilities. Johannes often enters Mikuni's antique shop without permission and performs experiments on his beloved dolls, which of course angers Mikuni a lot, but Johannes doesn't seem to be bothered by his tantrums.
- Strength: 4/10
- Tactics: 6/10
- Cooperativeness: 1/10
- Mental: 9/10
- Appearance: 4/10
- Knowledge: 10/10
- "Welcome back, Miku-Miku. I have something important to tell you, Mikuni. I broke one of your precious, precious dolls, you see. But that's because...I keep telling you not to leave your things where I can reach them. Seeeeeeeee? Look! Her head...popped cleeeeean off, didn't it~? But it's all right...because I melted her head into a special juice for you. Now you can be one in both body and soul with her. Cheers!" (Chapter 28)
- "Me? His 'friend'?! That's so gross." (Ch.29, about Mikuni)
- "It's time...for the doctor...to perform...a little experiment." (Ch.29)
- "Johannes Mimir Faustus. That's my name, boy! You know, my label. Call me Doctor...or Johannes...Johan. Hans. Faust. Whatever you like, really." (Ch.29)
- "Now, hurry, hurry. hurry!! Let me touch your vampire! Let me examine it! Let me experiment on it!" (Ch.29)
- "Ahhhhh~! Such a mystery has come before me!! Cheers to the limitless possibilities this world offers!!! Time...freeze us in this blessed moment...such beauty...it brings tears to my weary eyes..." (Ch.29)
- "I'm sailing a ship...I'm going back against the flow of the river. From downstream...to a far higher upstream. If you want status quo...you go with the flow. But to stop it, go against it. People can't stay in the same place forever. They must...always seek out new things. Yes! You have to take those first steps! You'll never accomplish anything if you don't do something first. Satisfaction is stagnation! Stagnation is death! I want to know! To see! To experience!! To feel! To understand!!" (Ch.29)
- "Thank you for this moment!! Time, stand still!! Scratch that, don't stand still. I couldn't experience this if you did." (Ch.29)
- His character is most likely a reference to Doctor Heinrich Faust, the main character from the German drama "Faust" by Johann Wolfgang von Goethe
- In that story, Faust signs a pact with the devil "Mephistopheles". He agrees to serve Faust, make all of his wishes come true and grand him endless knowledge, while Faust sells his soul in exchange and has to serve Mephistopheles forever after his death. Johannes' intense desire to gain new knowledge and to understand everything even beyond the normal human world is very similar to Faust.
- As his name suggests, he is originally from Germany.
- His star-sign is Virgo.
- His favorite food is plain bread.
- His favorite drink is sparkling water.
- He dislikes stagnation.
- His hobbies are experimenting and writing in mirror (such as how he wrote on Mahiru's forehead).
- He is left-handed.
- His favorite color is lime green.
- His username on Servamphoto (a parody of Instagram) is "DrJohannesLab.".