Maybe it still to early to assuming something,,, are they really the only left person on earth ? I dont know.,,

This could just be two hikikomori living out their lives in a virtual reality simulation. In fact this scenario is almost ideal for someone with melancholia.

a quick game for anyone to play:
if you see a series tagged as "Age Gap", flip ten coins. if any one of them landed on heads, then you can rest assured that the series will probably be about a pedophile

Interesting considering how many age gap stories on this site don't feature kids at all.

Actual pedophilia (sexual attraction to young children) is comparatively rare within a public body. Sexual attraction to pubescent adolescents (Hebephilia) and older teens (Ephebephilia) is much more common. Fun fact: young adult women aged 16 to 19 are the demographic most likely to be raped or assaulted. Most hentai porn concentrates upon that age group, and a lot of it condones rape and harassment of these women. If you're worrying about the prurient and legal ramifications of a casual age gap manga, I can assure you that it's much more wholesome than the so called "mainstream".

^ Not to necessarily excuse the premise, but sleep deprivation is known to result in hallucinations.

Yes, but normally these are visual hallucinations, sensory ghosts created during a liminal phase of conciousness that exists very briefly before the person either dozes off or forces themselves back to wakefulness. One does not hold long conversations with them, nor do they involve auditory or tactile sensations.

No. The anime only covered her freshman year in high school, and that arc concentrates on her introspection, without major character intros.

What is her obsession with Schwarzenegger movies?

"I'll be back"?. Seriously she keeps coming back for more humiliating rejection. Like a soulless, monotonous automaton.

morosexual.

I dunno what this means but I'm stealing it.

Morosexual: A person who systematically pursues partners with a significantly lower IQ than themselves (Urban Dictionary)

We see Marie ordering around the maids here and even her master, and it looks normal to them, but then, they don't seem to be seen as autonomous people. We see the police asking where the master is, as is normal in Japan when they see a wandering kid (but they ask for their guardian, not their "master").

On the other hand, the lack of adult beastkins is puzzling. It almost looks like beastkins are grown in vats and appear out of thin air. Because if they have parents, or there are adults of their race that can take care of them, this society is cruel. Parents are never mentioned. Young beastkins are just conditioned in their institution to wait for their future master.

I am going out on a limb here, but one possibility is that we're not on Earth (or some fantasy world analog) but on some alien world where the Beastkin (a human name btw) were the dominant intelligent species. And then human colonists appeared in orbit, armed with superior weaponry and proceeded to wipe out the native sapients. A few hundred years later the surviving indigenous population languish in forced labor camps, but remain unbroken in their resistane.

Enter the Institute (full name the Mengele Institute for Beastkin Betterment. Official motto: Work Will Set You Free) and its pilot program of indoctrinating orphaned or separated Beastkin children in their subordinate status within human culture. These children receive enough education to navigate human society, but nothing beyond the fourth or fifth grade level. The most obedient children are then parceled out by the government to loyalists among the ruling elite to work as domestic servants that are dependent upon their human masters for survival. The goal is that these children accept their position as beasts of burden, so that eventually they'll be used in a captive breeding program, and their children will adopt their mothers submissive attitudes. Selective breeding will be used to identify and promote individuals with desirable traits of submissiveness and obedience, to be passed on to their offspring. (Itou Hachi could have been inspired by the Russian Fox Experiment for this dystopian nightmare. This is the dark flipside of Moe.)

Incidentally Sophia and Mel's master are more progressive in their treatment of their wards. But that's about it

How dare you! How dare you raise your hand against a beastkin girl and strike her down! I don´t even know your name, dipshit, but you just skyrocketed towards the top of my list of anime/manga characters I want to kill!

Easy there! A beastkin kidnapper is only the tip of the iceberg here. This manga is basically the Handmaid's Tale with furry lolis. The beastkin are basically slaves of humanity, marked and treated as property. And the whole reason that Mel and Marie are orphaned? Genocide.

Repeat after me: there can be no retaliation without escalation. The idea from game theory is that any act of aggression must be met with a disproportionate level of response as a deterrence against further attack. Or as "Untouchables" called it, the Chicago Rules. Although admittedly this was.... excessive (the baseball bat? Sure. Verbal abuse? Okay. Stabbing them with scissors? ....Dafuq is wrong with you?!

Repeat after me: there can be no retaliation without escalation. The idea from game theory is that any act of aggression must be met with a disproportionate level of response as a deterrence against further attack. Or as "Untouchables" called it, the Chicago Rules. Although admittedly this was.... excessive (the baseball bat? Sure. Verbal abuse? Okay. Stabbing them with scissors? ....Dafuq is wrong with you?!

Oh! The blood drinking and her costume gave Kousaka-san away. She's a youkai known as a Hinoenma or Enshoujo, a female vampiric seducer that drains men of their blood and ki to maintain their youth and beauty. They are depicted as young maidens wearing traditional clothes and an umbrella, and reside in remote villages and farm houses. And they have a hidden pair of wings. The difference here is that Kousaka-san prefers young girls rather than guys.

I have a theory about the backstory and possibly the plot of this manga. It's a bit left field, but its cogent.

If you're not familiar with Shakespeare's "The Tempest", there is a major character named Caliban, who is a Cambion (a half man/half demon creature) who was born of a witch named Sycorax. In the prologue, the magician Prospero came to the island Caliban lived on, and defeated the Cambion. Caliban was only loyal to Prospero because of his fear of his master's magic, otherwise his only bit of obedience was extreme filial loyalty to his mother.

Here's the backstory for 1 x 1/2: Ayuko is a witch, a member of a women's only subculture or coven hidden in the modern world. This particular group obtains magical power by contracts to demons known as Incubi (singular: Incubus). An Incubus is a shadowy shapeshifter, a seducer and rapist, known for their ability to dominate humans through magical will. Though considered Male in the West, in reality they are possibly intersex, capable of Male and Female attributes.

Entering into a contract with these demons requires a ritual consisting of the summoning witch, and a sibling pair that plays Male and Female to match the demon's genderfluidity and be both a vessel and a bridge for its spirit form. This is a dangerous ritual given both demon's power and lust. When Ayuko, Atsushi and Akira (hey, alliteration) attempted a summoning, they seemingly lost control of the Incubus, which murdered Atsushi and sexually assaulted Ayuko. And the result was Ayuko being impregnated with Asuka.

I say "seemingly" because Atsushi's death may have been a life-for-a-life blood sacrifice, with Ayuko receiving a half demon daughter that would give her immense magical power required a necessary price paid in blood. But because it killed Atsushi, and because Asuka is dangerously unaware of her power and legacy, Ayuko felt very little warmth for her child. In truth she treats her daughter like a servant or an important work animal, which in fact she is. In spite of Asuka's filial loyalty, Ayuko only begrudgingly accepts her, and was often cold and even borderline cruel in her regard. In fact she has a magical "leash" around Asuka that enables her to suppress her demonic nature, including her sire's lust and will.

But all of that has changed in the course of a few weeks. Which brings us to the incest issue. In small tribal communities, where everyone is a cousin to everyone else, incest is anathema. So much so that they held divine punishment to be quick and decisive. But if punishment didn't happen, then it was because those supernatural forces that governed the world favored the incest. It then would be an opening into even greater magical power. As Akira pointed out, incestuous desire shouldn't occur between a witch mother and Cambion offspring because it is a divinely proscribed taboo (it's too much magic for one mortal to control). For it to be absent is evidence of hidden supernatural agendas. This is why Ayuko indulges her daughter's carnal desires to a limited degree, because she's unsure of the intent or source of this inversion. But some powerful supernatural entity wants Asuka and Ayuko to mate, for unknown reasons, and with an uncertain outcome.

The old woman is the last of her family line. There is no left one to inherit it, and therefore it is useless and forlorn.