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Main Universe


Story order
Experimental Organism A-3 Archangel Ranael →
Seraph Eden Black Alice →
Level: Battle 1: 115
Battle 2: 230
HP (Normal): Battle 1: 20000
Battle 2: 60000
Experience: Battle 1: 200000
Battle 2: 700000
Skills: Battle 1: Warmth, Softness, Pressure, Suction, Tenderness, Wind Spirit Summon, Temperance
Battle 2: Swede Demosu, Stipe Suck, Swede Gigantea
Area: Remina
Appears in: Chapter 1, 2 & 3
Artist: Setouchi

Promestein is a powerful angel scientist with vast technological, magical, and alchemical prowess. Despite her constant presence and actions in the world, she seemingly follows Goddess Ilias's cause without question, having created the chimeras on Ilias’s order. Despite being the Ninth and lowest rank of the Hierarchy of Angels, Promestein is quite powerful, and in fact, one of the leaders of Ilias’s army due to her vast knowledge of technology and command over the chimeras. She is also the leader of the Seekers of Truth.


Promestein’s personality is very calculative in nature, showing no emotion in any of her appearances and speaking very little, other than to observe others and introduce herself. She does show some levels of sadism however, as seen when she lays siege to the Monster Lord’s Castle at the end of Chapter 2. Furthermore, she is prone to arrogance; often underestimating her opponent's abilities to cope with her creations and developments, though she is willing to admit when she failed to account for something (such as Queen Alraune's Aztec Rose poison). She also tries to stick to the progress of her plans as much as possible, even if it means upsetting her own creations.

Although she puts on a front of serving Ilias, Promestein secretly despises her as she is aware that Ilias did not actually create the world. As a young angel, she refused to accept that everything in the world happened because of Ilias and her questioning led to her being ridiculed by other angels. Ultimately, Promestein serves only her own interests. She conspires with Black Alice to betray Ilias, and attempts to betray Black Alice as well.

She also deeply admires the human race, despite using them for cruel experiments, toys, or semen slaves. Promestein believes that they shares many similarities to her, specifically a thirst for knowledge and growth and use of technology, which is why she blatantly trespassed Ilias's law of not coming into contact with humans and introduced them to fire. She loves them so much that she even declared all of humanity as her rightful successor.


Monster Girl Quest trilogy


Several hundred years ago, Promestein was a capable worker who worked in Heaven's library and was monitored by Hermes. However, Promestein had an insatiable curiosity of how the world works, but was constantly told all phenomena were simply because Ilias wills it, and as a result other angels made fun of her. After seeing how humanity struggled to live their lives by just blindly following Ilias, Promestein introduced fire to them, but by breaking the rule of coming into contact with humans, Promestein was condemned to prison for hundreds of years. During this time, she dissected any small creatures that wandered into her cell, created various alchemical tools, and studied complex formulas to grasp the truth. About 500 years prior to the events of the game, Black Alice eventually bargained for Promestein's release, creating an alliance between the 8th Monster Lord and the angelic scientist.

Chapter 1

Promestein first appeared as Luka drags Alice out of the Haunted Manor, bringing supplies to Chrome to help her in her research, but finds out that she has left. She immediately recognizes Alice as the Monster Lord then quickly leaves.

When Luka returns to Lily's mansion at the Witch Hunt Village, Promestein is there, suggesting that she helped or supplied equipment to Lily for her crude experiments. She sees Luka, but leaves shortly after. Luka asks Alice if Promestein is a monster, but she isn’t able to trace any sort of monster blood or power within her.

Chapter 2

In Grangold, Alice hypnotizes a female magic engineer to reveal how they detained the Queen Ant. She reveals that five years ago, a strange scientist woman, identifying herself as Promestein, came to them and gave them advanced technology, and has been freely supplying it to Grangold over the years, but recently stopped coming and the machines began to malfunction. The engineer also mentions that Promestein wanted Grangold to test her machines and supply her data, also saying that the seal on Queen Ant was a prototype for sealing the Monster Lord herself, much to Alice's shock. Later, Luka asks if Promestein is human, but Alice doesn’t think so either.

Luka then encounters the scientist again at Remina. At first, he assumes she lives there, but then realizes she may be involved in the massacre.

After Luka revolts against Ilias, Promestein appears leading the attack on the Monster Lord’s Castle, revealing that the chimeras were all her handiwork. Luka yells that their defeat will never happen, until Granberia and Alma Elma receives smack-downs by Arc-En-Ciel and Hainuwele, respectively. At this point, Amphisbaena, Tsukuyomi, and Rapunzel also appear on scene; the true masterpieces of the chimeras created and modified to exploit the weaknesses of the Four Heavenly Knights and the Monster Lord. Luka attempts to attack the mastermind, but Promestein dodges using the artificial wind spirit Zylphe and explains that by analyzing the originals she is able to create and is mass produce artificial Spirits. Alice reminds Luka that he’s not alone in this battle, and though they are faced with angels and chimeras closing in from all sides, the angel who’s mass producing weapons, plus the one pulling the strings, they charge into the fray together.

Chapter 3

Promestein watches the destruction unfold in the Monster Lord's Castle, but when Luka manages to defeat Cupid, Valkyrie, and Archangel Ariel, Promestein calls out to Eden, the commander of the angelic forces, a failure. Alice then decides to attack Promestein; Arc-En-Ciel, excited, tries to step in, but Promestein stops her as there are already countermeasures in place against Alice and Luka. Alice punches at her, but Promestein, using the same barrier magic from Grangold, manages to seal Alice, much to Luka's horror. Promestein explains she had studied a seal called the Six Ancestor's Great Seal, used to seal Alice I (First) as well as the six ancestors of all monsters, and successfully reproduced it. Promestein then uses her countermeasure that was designed for Luka; he notices that the power of the Four Spirits has completely faded. She then explains that she managed to develop another seal that blocks out the nature of elements over the entire world. A Chimeric Beast attacks just to prove her point, effortlessly avoiding his diminished Lightning Sword Flash and even driving through his parry. Promestein then offers Luka a choice of surrender or refusal.
If Luka surrenders, he is taken to the Drain Lab, where Radio rapes him using various machinery all over his body. This rape scene is added to Promestein's first Monsterpedia entry as "Rape Scene 2" and is required to complete the Monsterpedia.
Upon Luka's refusal, Promestein orders Amphisbanea to sever Luka's limbs, but a large vibration interrupts her; revealing itself as Tamamo with the unsealed Giganto Weapon. It manages to annihilate most of the chimeric forces, but is easily defeated by Arc-En-Ciel. Promestein is surprised at the beast's resurrection, noting it as a "relic from the Great Monster Wars", further commenting that she didn't expect anyone else to have the knowledge of how to reactivate it. She then explains to Arc-En-Ciel about how powerful the Giganto Weapon was at full power, noting that currently it's power had degraded substantially over the centuries. She then tells Luka that nothing can stop her five top chimera, dubbed Next Dolls. Promestein orders the Castle mopped up, but Tamamo steps in, noting that the chimera forces are mostly comprised of beast creatures. Her aura alone is enough to terrify the Chimeric Beasts; Promestein orders a withdrawal as they already have accomplished their goal in weakening the two most threatening monster forces, much to the dismay of the Next Dolls. Luka chases after Promestein, ignoring Tamamo's warning.

Luka suspects Promestein is hiding out at Remina and heads there, where a strange girl (Black Alice) leads him into Promestein's secret laboratory. Promestein is a bit surprised to find Luka in her lab, along with a young Alice who appears after causing destruction in the lab (limited to waist height), revealing that she  partially escaped the seal using magic she had learned from Tamamo; throwing her original body into subspace and transferring her consciousness into a younger, weaker body. Promestein, acknowledging the weakened forms of her foes, transforms into a seaweed-like monster, boasting that it once belonged to an ancient creature, and then attacks. Alice manages to hit Promestein, stating that her experimentation resulted in her degrading from an angel to a monster and thus the loss of her intangibility, but Promestein continues boasting. During the battle, Luka and Alice aren't doing so well until Luka suddenly enters Serene Mind despite Undine being sealed. Promestein resorts to using Zylphe, but Luka is still capable of reading her flow, which Promestein calls nonsense. After being driven back, Promestein attempts to inject herself with a syringe, but Black Alice appears and stops her, stating that it is too early to use the White Rabbit injection and teleports her away.

Promestein then awakens in the Drain Lab, having returned to normal and recovered from her battle injuries. There, she meets the members of her Seekers of Truth: La Croix, Laplace, and Lucia. Promestein reports that even though the Monster Lord and Fake Hero have been weakened, they are still not completely powerless, and that Black Alice is aware of the White Rabbit. She then notes that she and her subordinates are all from different races; Angel, Monster, Machine, and Human, respectively; and they all share one thing in common: they are seekers of truth, overcoming any obstacle in their way including a god while recruiting other truth-seekers. Promestein then orders La Croix to not let anyone near a device and Laplace to gather energy for what is to come, and Lucia then leaves for her hometown Witch Hunt Village as a "messenger of slaughter and destruction". Laplace cannot fathom why Lucia cares about a village in the middle of nowhere, but Promestein responds that she is going to destroy it; Laplace thinks human thoughts are too irrational, something that Promestein approves of. All four then part ways, but the very same Cupid that aided in the assault with the Monster Lord's Castle arrives momentarily and discovers the Drain Lab then goes to report to Eden.

Sometime later, Ilias questions Black Alice about what she did with the "White Rabbit". Ilias comments that the plan may go astray if Promestein's body were to be broken, and then states that no matter what one drinks, they will not become the same as a god, and even so it isn't as pleasant as one thinks.

In an intermission during Luka's travels back to San Ilia, Promestein informs Ilias that she will erase her shame with her future work and reports that her entire forces, except the Next Dolls, are left under Eden's command. Ilias reminds Promestein about the pardon on her sin.

After Luka reclaims Gnome, Promestein calls Eden a failure once again. Eden rants that it's her chimeras that are failing to do their jobs, and Promestein retorts it was unexpected and she needs to delve more on her research. Eden then tells her that she can read her plotting from behind the scenes and that she does not trust the scientist, but Promestein (sarcastically) says she's a heartfelt supporter of Ilias.

Later on, after Luka reclaims Salamander, Tsukuyomi and Amphisbaena apologize to Promestein for not being able to perform their duties. Promestein is impressed at how Queen Alraune's Aztec Rose managed to sufficiently weaken Tsukuyomi, and dismisses Amphisbaena's failure to kill Erubetie as being due to Throne Eggiel being unable to stall Luka long enough for the chimera to finish the job, and again calls it a failure on the part of Eden. Laplace then asks about Lucia, and Promestein suspects she has failed and defected, and says Laplace couldn't possibly understand it due to her AI logic. She then discusses that "White Rabbit" is advancing, and how she must be aware of Black Alice's actions since she knows about it, although they can ignore the useless Seraph. After Promestein dismisses her chimeras, Cupid reveals herself, having overheard the conversation and leaves to report to Eden.

Once Luka recovers Undine and thus has reclaimed all four spirits, Black Alice and Promestein both tandemly insult Eden by calling her names for her massive failure in invading the world, and comment that Ilias will be very angry. Eden rants that they have failed too, but the two say that as the commander of the forces she bears the responsibility. Promestein leaves afterwards, sarcastically saying she doesn't want to trouble the "great Seraph" much.

In the Drain Lab, Laplace wonders about the meaning and nature of her existence and asks La Croix about it. The machine asks why Promestein gave her human thought patterns. La Croix mentions that Promestein has a deep passion for humans; in the ancient times, it is said that she rebelled against Ilias to give knowledge to humans, and was confined as a grave criminal as a result of that crime.

After the defeat of Lucia, Laplace, and La Croix and the subsequent destruction of the Drain Lab, Promestein notes that she is now the only remaining Seeker of Truth left standing. Promestein also discovers in a report that Laplace delayed the destruction of the Drain Lab, setting a five minute delay rather than blowing it up immediately once compromised, and wonders if Laplace had found her answer in the meaning of her existence. She then reminisces on her past and how she came to where she is currently. At this point Black Alice appears and the two discuss their alliance. Knowing they are being spied on by Cupid, Promestein asks Black Alice to dispose of the spy as they no longer need Eden's watchdog when their meeting ends.

When Luka finally reaches Heaven, a dismayed Eden leaves to challenge him. However, with Eden out of the way, Promestein and Black Alice initiate their plan to betray Ilias, using the Six Ancestor's Great Seal on her while Black Alice injects the White Rabbit, containing Alice I's genes, into herself and devours the goddess, becoming the ultimate entity of light and darkness; Promestein explains her hypothesis that infusing a being with dark and holy energies will create an all-powerful being. Promestein then goes to deal with Luka and Alice before initiating her and Black Alice's compromise on ruling the world together, but before leaving she mentions that Black Alice leaked information about Ilias's second wave to their enemies resulting the fall of Promestein's chimera army including the Next Dolls; Black Alice just laughs.

Promestein confronts Luka and Alice, noting the casualties of the heavenly forces and chimeras, but refuses to stand down as it is all part of her and Black Alice's plan of becoming the ultimate entity. Promestein then injects a variant of the White Rabbit optimized for her and transforms into a towering seaweed creature, planning to consume Luka for his holy power and also become the ultimate entity herself, implying to betray Black Alice. However, even with this new power Promestein still falls joint to the hero and the monster lord, but while melting away she declares all of humanity as her successor, believing that their thirst for knowledge will eventually surpass Promestein's work and research. Alice acknowledges that humans have incredible technological growth, which is why Promestein deeply loves the human race and why she gave them fire. Promestein then mutters that humans will surpass gods before finally disintegrating into dust, leaving Luka and Alice to ponder about the future of humanity before moving onto pressing matters. However, once Black Alice falls, Ilias emerges from her remains, revealing that she intentionally allowed Promestein and Black Alice to betray her in her true plan of becoming the ultimate entity.

One month after Ilias's defeat, Luka, Alice, and Lucia discuss about Promestein's final words, agreeing that technological advancement is neither good nor evil, but a phase in science. Lucia also mentions Promestein saying that technology is neither blasphemy or human arrogance, but the application of the knowledge gained. She also says that Promestein took her work too hastily, leading to her own downfall.

Monsterpedia Entries


“An angel who studies biology and technology that serves Ilias. Though she is an angel of the ninth circle, she was given a special mission by Ilias. Her original body was that of a normal angel, but she has since transplanted an ancient seaweed that she spend generations researching. She seems to have fairly high prowess for combat.

The original reason she had for going against the Goddess’s will and studying science is not known. It is only known that she was imprisoned as a criminal angel before Ilias gave her an important mission. A very strange existence among the angels, her fellow angels refer to her as a Heretic sometimes.”

Promestein (Final Form)

"An angel who dedicated her life to the pursuit of knowledge. She imbued her own body with the genes of an ancient form of monster seaweed, in order to become closer to Dark God Alipheese's power. But, unable to control that power, her body explosively expanded. Even this runaway power was predicted by Promestein, though. After assimilating with pure holy energy, she was expecting to be able to stop the runaway power and maintain control.

Taking advantage of the re-creation of the world, she intended to betray Ilias. Her true aim with Chimeric research was to create an army able to defeat the armies of the Heavens. Her Next Dolls, ostensibly created to counter the Heavenly Knights, were also supposed to be used to defeat high ranking angels. In the end, all of her creations were destroyed, and she fell at the hands of Luka himself."


First Battle

Warmth: Normal attack that damages once. Triggers Facial Bukkake on defeat.

Softness: Normal attack that damages once. Trigger Breast Bukkake on defeat.

Pressure: Normal attack that damages once. Triggers Tentacle Bukkake on defeat.

Suction: Draining attack that damages twice. Triggers Plant Bukkake on defeat.

*Wind Spirit Summon: Leads to Tenderness on next turn.

Tenderness: Binded attack. Leads to Temperance on next turn.

Temperance: Binded attack that leads to one-hit KO via instant follow-up. Follows Tenderness.

Second Battle

Swede Demosu: Normal attack that damages thrice.

Stipe Suck: Normal attack that damages twice, second hit has drain properties.

*Wind Spirit Summon: Causes all attacks to hit five times.

*Summon Earth Spirit: Causes all binds to become inescapable.

Swede Gigantea: Triggers bind status. If not escaped within two turns, it leads to a one-hit KO via instant follow-up.

*Non-requestable technique

Battle Overview

First Battle

A very difficult fight, hence she is being one of Ilias' right-hands. She can dish out a lot of damage, making Meditation a necessity. Alice will help to some extent, but she is not as powerful as she was before.

Promestein is initially too powerful to the point where she can outdamage his healing. However, when she attacks Luka when his health is very low, he will enter Serene Mind, granting high (~80%) avoidance and costing now 2 SP instead of 4. However, Temperance, which occurs right after Wind Spirit Summon, will still hit him, so Guard is necessary. The rest is straightforward; attack normally and use Meditate and refresh Serene Mind as needed.

If Luka succumbs, Promestein's left arm, a large flower-like organ, attaches itself to Luka's penis and sucks him dry. The rest of Promestein's plant-like body then surrounds itself on Luka and devours him entirely, resulting in a vore ending.

Second Battle

Although this is Promestein's final form, this battle is actually not too difficult, as all she has are high damage attacks, wind and earth spirits, and a bind that leads to a one-hit KO. Keeping the Four Spirits up will easily counter all these, and go on the offensive and she should go down quickly.

If Luka loses, he is pulled into Promestein's large plant predatory organ where he is eaten.



"Research like that is complete heresy. There’s some use for it but… …Excuse me, you don’t need to hear about that. I, the pure Ilias, shall guide you. During this fight, you should regain your serene state of mind. Once you do, make sure to never lose it. With that, you’ll be able to avoid most attacks… But if they hit, they are painful, so always keep an eye on your health. In addition, after she summons the wind spirit, she will use a powerful attack. Make sure to guard if you wish to survive it. Since your opponent has a large amount of health, expect a long fight. Keep an eye on your SP, and make sure you always have enough to recover and keep your serene state. Now go, oh brave Luka. Don’t hesitate to beat that great sinner to a pulp."

Promestein (Final Form)

"Promestein... Just how far did your horrible research go? You've become a true demon, at last. Divine punishment awaits. Close in form to a monster now, a serene state is effective. Fallen angel dance isn't too effective, so Sylph need not be called. Her restraints are also powerful, so Gnome is required. The damage reduction will help a lot, too. As before, make sure to summon the opposite attribute if she summons a spirit. Her HP is very high, so prepare for a long fight. Now go, oh brave Luka. Make her taste the thousands of years of my anger..."

Rape Scene 2 of First Battle

To obtain Promestein's 2nd rape scene in the Monsterpedia, surrender to Promestein near the beginning of Chapter 3 after defeating Archangel Ariel by selecting "Acceptance" when given the options of accepting, or refusing Promestein's surrender request.


  • Her name is a portmanteau of Prometheus and Frankenstein. This references her tendency in-story to “gift” humans with arcane knowledge and fire, in the same way Prometheus gifted humans with fire, along with her and Frankenstein both being “mad scientists” who try to create life. All three characters also defied gods, although Promestein allies with Ilias as a means of achieving her goals. It is worth noting the full title of the original Frankenstein novel is Frankenstein; or The Modern Prometheus.
  • In her human/angel form, her angel wings and halo appear translucent and white. However, in her pure angel and monster/angel form, they appear solid and gold.
  • Promestein has performed the most antagonistic actions directly in the game:
    • Aided Chrome's, Lily's, and Grangold's research and experiments.
      • Chrome's experiments involved desecrating the dead around the Haunted Manor, despite having no ill intentions.
      • Lily created havoc in the Witch Hunt Village, mutating or killing its citizens with her experiments.
      • Grangold's technological advancement eventually culminated into their capture of Queen Ant, and sparked an incident when she broke free.
    • Created the Chimera and the Artificial Four Spirits, who were one of the heavy fighting forces in Ilias's second full scale war and the former had even participated in the Slaughter of Remina. The Chimera Dryad additionally caused an incident in the Forest of Spirits, although presumably on its own and not under Promestein's order.
    • Led the Seekers of Truth, who all also participated in Ilias's war.
    • Captured humans during the war and forced them to undergo experimentation, semen slaves, etc., monitored by her fellow Seekers of Truth.
    • Spearheaded the assault on the Monster Lord’s Castle.
    • Installed the Six Ancestors Great Seal on Alice in an attempt to remove her from Ilias's war. Alice's countermeasure instead sealed her main body and left her in dramatically weakened form.
    • Installed a worldwide seal on the elements of wind, earth, water, and fire via the Four Towers, dramatically weakening the Four Spirits and Luka's control over the elements.
    • Created the White Rabbit, attempting to produce an omnipotent, destructive entity out of herself, Black Alice, and unknowingly Ilias.
  • Promestein is the only Seeker of Truth whose name does not start with a "L".
  • Her theme is J. S. Bach's Ruht wohl, ihr heiligen Gebeine from St. John Passion. In a strange coincidence, her version sounds a bit similar to Lilium, the sorrowful opening song of the anime Elfen Lied, which is also in part about the cruelty and madness of uncontrolled research for the sake of research. If this was done on purpose is unclear.
  • Strangely, despite Ilias's and Micaela's claims of holy and dark energy being naturally incompatible with each other, Promestein successfully created creatures mixed out of angel and monster genes (including her modifications on herself) and also designed the self-destruct sequence of the Drain Lab to utilize a mixture of holy and dark energy.
  • Her character could be based from Kurisu in Steins Gate series as they're both scientist and have similar designs.


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