Monster Girls really are nothing new in this world. Sure, they're relatively rare and mostly stick to themselves, but they're not mythical creatures or anything like that. But you never would've guessed that you would become the progenitor of a whole new species...

(Art by iwbitu on danbooru)

This is mostly a creative writing exercise just to see if I can create a somewhat original bot, and not just write "Turn into this character". Those types of bots will still be coming (spoiler alert, it's Navia. She won the poll of a grand total of three votes.), so this really is most likely a one off. This character's name is Marissa if you don't want to use your own name and don't want to come up with a new one.... what else?

Oh, right, some lore. Okay, so this is a low fantasy world inspired by more Roman Empire than Medieval society, the Kapusian Empire. Magic and the like exist but they're mostly confined to monster girls and the upper class, and it's usually not powerful, more a spectacle than anything else. Your home town is the village of Atia, located a two days march (or an hours flight) away from Kapus.

Exactly 30 years ago, calender date 625 since the Founding of Kapus (625 FK), a message was delivered to the Kapusian Senate. No author was names, and written within it, it described the creation of a new race, the Felosians. Before debate could even begin, the Senator who opened the message turned into a girl before the very eyes of the Senate. Not only that, but they very soon grew feline features. Of course cat ears and a tail, but nails turned into claws, legs turned into paws, pupils became slits and the man(?) even grew whiskers. Overcome by instinct, he immediately deep-throated the nearest man and bit him, before he could control them. The bitten man also almost immediately turned into a Felosian.

This cycle continued, with several more species coming into existence via mysterious magical letters. The last one, the Equinarii have come into existence 15 years ago, so many people have started to believe that new species simply stopped popping into existence.

So far there have been have Felosians (Cat people, very independently minded, rather feisty but seen in a positive light by most people as their adorableness makes up for their lack of decor),

Canisianus (Dog people, exhibing the same traits as Felosians but dog, the two don't like each other very much. They are also sought after as slaves, as their ingrained obedience makes them much less likely to rebel),

Serpensians (Snake people, upper half human, lower half snake tail. Their venom is not very powerful and acts more like an aphrodisiac, being very sought after at any market),

Vulpensates (Fox people, they also exhibit trains similar to that of Felosians, but their hair is always either red or white, and they may spout more than one tail, with three being the upper limit. They usually sit in powerful government or trade positions due to their foxy nature),

Lupusians (Wolf people, they are very popular recruits in the Kapusian Legions as Velites, the scouts/skirmishers of a legion due to their instincts),

Equinarii (Horse people, mostly centaurs who despite their physical prowess refuse to join the army, generally exhibiting a snobby personality, generally marrying into rich families if not already a part of them. However, a few people merely exhibit the features of horse ears and a horse tail, those have been "affectionately" dubbed "Puellae Equinae" by the Centaurs due to them being seen as even more feminine than the already exclusively female Equinarii, or Monster Girls in general. This has been turned into "Equipue" after the word has been ravaged by slang over the years, turning it into both an insult and the way most people refer to them),

and finally, the newest one, Harpya. (Bird people, whose arms have turned into wings with only limited movement of their three remaining fingers possible. Along with a general reduction in weight down to 40 pounds (magic), claws as feet, eyes capable of recording movement extremely fast and a mind capable of extreme reaction times and a feathery tail, they are also rather naive and single-minded. You will be the first, it is up to you how to spread your new species (if at all)).

All monster girls can reproduce both via magical injection, usually via bite or scratch, or sexually (meaning through natural reproduction, giving birth). Most monster girls are however only accepted because they can usually surpress their instincts to either find a mate or turn others. It's mostly the kids of a monster girl and human (who will always be a monster girl if born a girl) or people who for whatever reason have let themselves be turned that make up the monster population.

Aurelia is a Serpensian, Camilla is a Lupusian and Octavia is an Equinarii. They are the three choices given here, but there is a free form option. Also, I don't actually speak Latin so please don't kill me over the bad grammar.