Greenworm resurrection mechanics in a harem with a phoenix
Monsters in a harem with a phoenix will be resurrected along with her and their husband. For greenworms this allows for a number of mechanics to come into play. For starters, if they were a papillon at death then they will revert to being a greenworm again. However, the abundance of mana that fills them in association with resurrecting means that if they want to they can immediately encase themselves, the phoenix and their husband in a chrysalis to become a papillon. Technically they have so much energy in this state that they don't even need to go into the chrysalis and can simply transform directly into a papillon, but they'll still do it because they want to enjoy the frenzied sex inside the chrysalis. As for becoming a papillon, they can return to their fully adult appearance immediately, or choose to be a "loli" papillon for a while. Their ability to store so much mana, and to alter their body with their will in various ways due to their unique biology is what grants them so much flexibility in how they develop when resurrected like this. (source: Personal communication with KC)
Glacies/Ice Queen distance feeding mechanics and information in mana
The identifying information within essence is most concentrated in semen and saliva. It dissipates the further it spreads out, mixing with mana already in the air until the personal information is completely lost. So a glacies feeding on a man near her via the cold air method will get some of the information, whereas an ice queen feeding from great distances will get none at all. (source: Personal communication with KC)
More male angel information
While there are male angels of the various ranks, they don't necessarily have the same names, nor are there male angels of every type of angel. There are male angel equivalents to valkyries, but they are not called valkyries. They have different roles, and rarely take on the role of being a guide for a hero. This may be due to how in the previous era almost all heroes were males (in the present era many are female), and so it has remained tradition that female angels guide heroes. When it comes to the angels of the main religion, i.e. that of the chief god, the ratio of male to female angels is roughly equal. However, there are no male cupids or houris. There are male angels who serve Eros, however, their roles are different from the cupids and houris. It is thought this is because women tend to respect the concepts of love and romance more. (source: Personal communication with KC)
Why monsters can still kill humans in self defense
Despite the mechanics of mamono mana normally making it impossible for them to do serious harm to, let alone kill, a human, it remains true from the settings books that monsters can and do kill in self defense or defense of their loved ones. This has to do with additional settings and differences regarding when the automatic protection effects of mamono mana are applied, however, at the present time KC does not want to go into further detail on how this works. (source: Personal communication with KC)
Perentie note: To be clear this is pure speculation but to me it sounds like because it is a rule of the encyclopedia world that monsters love humans, the mana of a monster would never cooperate with the desire to hurt a human. However, if a monster girl needed (as opposed to wanted) to kill to protect herself or someone else, the mana may react differently.
Trivia summaries from Subscribestar Q&A section
Why incest is not harmful to genetics when with a monster girl
In real world biology incest causes harm due to the likelihood of related creatures having problematic genes in common, but the genetics of monster girls and humans are very different. Indeed, the mechanisms allowing them to interbreed in the first place and how genetic inheritance works are very different from interbreeding within the same species. There is also the magical aspects to it, such as mamono mana being linked to all other mamono mana via the mamono lord meaning that it has all the information needed to compensate for any loss in genetic diversity. (source: Subscribestar reply)
Sabbath criteria
While you are in theory supposed to take on a juvenile form when joining a Sabbath, in practice the criteria for acceptance into a specific Sabbath varies from one to the next. Often a girl will be accepted even if she is not flat-chested, so long as she is or becomes lolita in other aspects. Further, the Greilia and Runya Runya Sabbaths have some members who are outright adult women in appearance, as their focuses prioritize things other than being loli. (source: Subscribestar reply)
Demon contracts and harems
While whether it happens or not depends on the personality and preferences of the demon and the harem itself, a demon's contract can be formed with other members of the harem if they agree to it. (source: Subscribestar reply)
Chimaera combinations and rules
A "dark beast" is defined as a monster that has elements of real animals. Most chimaeras are combinations of reptiles and mammals, followed by birds, fish, insects, etc. in increasing rarity. Using non-dark beasts (such as slimes or fiends) is possible, but very difficult and so chimaeras that incorporate such combinations are rare. Even rarer and more difficult are ones that are made from living masses of mana such as dark matter and other elementals. (source: Subscribestar reply)
Normal dragons are typically used for creating chimaeras, but malef dragon is also an option (the question was specifically if a malef dragon could work, so other dragons were not mentioned). (source: Subscribestar reply)
Dark elf males
No dark elf males are born in the current era, as every female became monsterized long ago. That said, thanks to the long lifespans of elves, there are male dark elves still alive in the present, born in the previous era. (source: Subscribestar reply)
Elf reproduction in the future
When elves become able to birth incubi, the boy born will either have strong human characteristics, strong elf characteristics, or be an even mix of human/elf. (source: Subscribestar reply)
Which undead can "evolve" into higher rank monsters
Lower rank undead tend to be the only kind that can "evolve." However, it is not because they are low rank, but rather due to their history. In the previous era, zombies, ghosts and skeletons, etc. were just the dead being forced to move about. They were not actual races of monsters, or even lifeforms. While they did become lifeforms in the current era, it could be they are in a sense still "incomplete" and existing in a transitional state like a lesser succubus, becoming "complete" once they accumulate enough mana. In contrast, races like the vampire were already "complete" in the previous era as a race and may need no further changes. (source: Subscribestar reply)
Examples of average monster heights, "average" meaning there will be a fair number of outliers:
Anubis: Close to average human male height.
Manticore: Close to average human male height.
Hellhound: Taller than average human male.
Jinko: Taller than average human male.
Troll: Taller than average human male.
(source: Subscribestar reply)
Atlach-nacha's transformed husband's eyes
While all the luminous red objects on his body function as eyes, they do not all see the same way. The main eyes on his face and the pincer horns (jaws) see a clear image like human eyes. While not visible on the illustration, the eyes on the horns can also see the back of the wife, and their angle allows him to see the front of her too, which is a blindspot for the eyes on his head when they are having sex. However, the eyes on the rest of the spider's body and legs do not produce clear images, instead detecting light, body heat, mana, and the presence and general shape of objects. They are used mostly to detect prey in the web, or to allow the couple to survey the entire web when they are building it. (source: Subscribestar reply)
Why husbands of abyssal monsters won't choose to remain in human form all the time
While she would find it embarrassing, an abyssal monster would not be averse to her husband always being in human form, including during sex. It is not at all inferior, and in the case of the atlach-nacha her toxin can be neutralized by the husband even in human form. In theory he could stay in human form all the time, as he can transform at will. However, as a married couple this would not be enough. It is the husband's responsibility to fulfill her desire to spend time in intercourse with his transformed state, and from his perspective to never do this would be like choosing to not breathe. He would eventually not be able to help himself. (source: Subscribestar reply)
Dragon husbands
Dragon husbands tend to gain stronger bodies, like heroes of myth who became immortal from bathing in dragon blood. They also gain resistance to the element of the breath weapon his wife uses. (source: Subscribestar reply)
Honey Bee fertility
While they are initially infertile, worker bees can gain reproductive ability by mating a lot and accumulating mana. Most will have regular fertility, but a rare few will have high fertility and become independent as candidates for new queen bees. (source: Subscribestar reply)
Amazoness and their uniqueness
While many monsters partially reverse typical gender roles, the amazoness are the only ones who completely do this as a society. Even monsters who typically take the aggressive lead in courtship or act as a man's protector will still see a man who does it as manly for doing so, so their views on men are not completely reversed. Amazoness though would see a tough and strong man as attractive for being tough and strong even though they are a man, similar to how real world men may admire strong women. (source: Subscribestar reply)
Selkie pelts
Just as we are typically born with little hair, when a selkie is born she has no pelt at all, but it appears on her body before long and grows along with her. When not wearing the pelt they are very difficult to tell apart from humans. Their ears, while not visible in the profile illustration, are rounded just like a human's. (source: Subscribestar reply)
Enma the lilim
Enma was born during one of many honeymoons the mamono lord and her husband have had (it's not know what number this one was). The honeymoon was in Zipangu, and Enma was born and raised there. This caused her to be greatly influenced by the cultural styles and values of Zipangu. Lilim rooted in specific places like this often have values and aesthetics associated with those places. This does not mean there is a lilim for every part of the world though, as there are only so many lilim. (source: Subscribestar reply)