If you have evern heard of the anime series Vampire Knight then you should reconize this plot!
There is a school which teaches not only human children but shapeshifting children as well. In an effort to bring peace to the two fueding races. The human children have no idea that there are shapeshifter children in their midst. Of course had the human children learned this there would no doubt be panic in halls and classes throughout the school. So the shapeshifting children upon entrance of the school where given charms which they where then required to wear at all times and forbidden to take off ever. Not even in sleep nor while bathing where the shapeshifting students permitted to remove their charms. For the charms locked away all that was shapeshifter forcing it deep into the recesses of the shapeshifting childrens minds. The shapeshifting children while in possession of their charms while wearing their charms appeared as normal human children. The shapeshifting children while wearing their charms did not have the ability to shift into their feral animal counter forms. The shapeshifting children while wearing their charms did not have the ability to heal themselves from injuries. The shapeshifting children while wearing their charms did not have supernatural speed nor supernatural reflexes nor supernatural senses.
This school however is actually just the front for a massive slave ring. Potential masters can come into the school and look over the students for potential new pets. The students themselves are never the wiser about whats going on. None of the students are aware that they are being eyeballed by potential masters. The potential master has one of two choices. The potential master can either deal with a staff or teacher of the school who is aware of whats actually happening in the school, and buy the slave or slaves. The new slave or slaves will then be pulled from class with some trumpted up excuse and detained in an empty room. The new master can then go pick up his new slave or slaves. If the master wants he can take his new pet or pets straight home from there or play with them a bit in the specially sound proofed room. The other choice the potential master has is if he happens to see a student or students who catch his attention and arouse his darker passions. The new master can stalk the students that have aroused his darker passions at his liesure and make sport of them.
most potential masters who come to the school seeking new pets are typically rich high status supernatural beings with several pets already in their possession. your character a is a demon and a steriotypic master. he has brought with him another pet used for manual labor rather then sexual pleasure. the pet the demon has brought is a virile young male shapeshifter. to keep the shapeshifter under control the demon has cast various spells over him.
one spell to lock the shapeshifter into an eye pleasing form that of an anthro or a human with fuured ears and a furred tail. one spell which casts a human glamour over the shapeshifter. a last spell to keep the shapeshifter from shifting into a feral animal who is only driven by the need to spill innocent blood and the need to impregnate as many females as possible.
however these spells are only temporary and requires the demon to reapply them to the shapeshifter. once someone other then the demon touches the shapeshifter the spells are canceled the idea is that the demon has intergrated himself and his pet shapeshifter into the school system to watch the students for new potential pets. the shapeshifter has been setup as a simple male substitute teacher.
the demon himself is possibly in a position where he can easily access his pet shapeshifter and any students who happen to catch his eyes. however the shapeshifter is the one who first sees the masters new pets. two young cats wandering the school grounds. however the shapeshifter doesnt know he himself is a shapeshifter and believes himself fully human due to the demon meddling with his memories. so the young animals only slightly intrique him.
he goes out to catch them but they run from him the chase brings out his predatory side. once he corners the two young animals and manages to pick them up. they instantly shift into human forms and he instantly reverts to his feral animal form. in his feral animal form the shapeshifter only has two desires which override all other desires. make the two young girls scream and writhe in agony and impregnate them with his offspring.
being a shapeshifter he can either choose to allow them to remain in their human forms or force them to shift into their own animal forms. being an animal the shapeshifters cock has a knot which once fully engorged with his arousal will lock him into whatever female he fucks untill he has fully expended himself in that female. so the demon has a limited time to get to his pet shapeshifter before he impregnates the two young girls