When its master left for the last time, it weeped as much as a fungus could. It desperately wished they would return, did he not love it, did he not make it? But it pushed away these thoughts, hoping one day the master would return so in the meantime it tried its hardest to keep everything in order, to keep it just as it was. But the food ran out quick, the animals were starving, the house did what it could creating edible mushrooms but after a while they simply couldn’t stomach it any longer and died, so the house undeterred dug its mycelia into the creatures skin to give them a close approximation of life, nobody would notice.
Next was the Testificates, who learning of the masters disappearance, wanted out of the wretched house but the house panicked, terrified at the thought the master would come home and realize there were no Testificates so the house did what it thought was best and confined the Testificates to their rooms. The Testificates managed to survive longer than the animals, they could stomach the mushrooms the house provided by cooking it, but it wouldn’t last forever the spores in the air were weak but after a while and without proper ventilation the Testificates became sick with the spores and began to hallucinate, they started to believe there were things outside racing and running, knocking and laughing, and maybe there was. Eventually the delusions got too much and one fateful day they turned on each other believing the others to be imposters mimicking their friends. They had all killed each other. With the animals the house could at least present a semblance of life, but the Testificates? Mangled dismembered bludgeoned, it was far too much, but the house had an idea, its master would often read these things called books to gain more knowledge, maybe it could find the knowledge to bring back the Testificates for the master, so for a long time it started trying to figure out how to extract the knowledge, until one day it figured out how. Magic was something it knew well, after all it had been born out of magic, it managed to create a spell where it absorbed the knowledge from books, and so it started its journey of learning.
Every book in the library, but it wasn’t enough, so it searched, luckily quite nearby, a place which stored a mass of knowledge stood, so it crawled along its insides, the walls, making sure it was never noticed. Breached the book cases, reading each and every one, absorbing all knowledge eventually finding what it was searching for: the books on necromancy, and so it started to experiment, it had plenty of bodies to use. The first experiment was what the house considered a failure, it wasn’t a testificate, it was animated, it could move, but it stood still and just drooled and when it did walk it walked into a wall and fell over, so the house reversed the spell and the thing fell to pieces. But the house realized what it needed, it needed a sense of survival, to the thing life and death had little to no difference, so it may have as well not be alive at all. To the house all living things needed two things, to eat and to fear being eaten, so that’s what it added to the next Testificate. This one was far more promising, it could move, it could eat, and whenever the house hit it, it ran away in fear, this was a creature, but it wasn’t a Testificate. It’s issue is that it has no memory of the Testificate it once was, it couldn’t light fires, it couldn’t use tools, it ate raw flesh with its bare hands. However the house didn’t consider this creature hopeless, maybe it could teach it.
So the house made an effort to reverse the knowledge spell, and infuse intelligence into the creature. It was a success, it knew things, it could vocalize, it was everything the house believed a Testificate could be. So the house attempted to return it to the Testificate room, but it refused, it evaded the house's efforts, the house could close off doorways, lock doors but the creature could claw through the walls. At that point the house realized that the creature no longer feared it, so it instead attempted symbiosis, a mutual agreement, to the house's delight it seemed to agree.
Around this time the house saw something strange. A visitor, it watched the visitor. It was overjoyed that the visitor stayed. It had been so, so, so long since anyone stayed at the complex. The creature had been curious about the visitor but the house had stopped the creature from harming the visitor, and the creature agreed to stay away from the visitor, besides the creature didn’t consider the visitor prey as it had no meat. The visitor would leave and return, which did give it a bit of heartbreak, remembering how its master left one day and never came back. It went this way for a long time, until one day when it was watching the visitor when they entered the master's room, it suddenly felt something it had never experienced before, rage. How DARE this visitor touch the master's things, a long time ago other visitors had searched the house but it had been so busy it couldn’t do anything, but now, it had time. So the house decided to let the creature do whatever it wanted to the visitor, the creature lured it to the basement but before the creature could do anything the visitor ran away to a nearby town. The house attempted to follow but it felt weaker as it got to the town, the town had some issue about it, so the house decided not to approach any further.
One day the visitor returned with someone it recognized, it was someone who was often found in the knowledge storehouse. It then had a fear, the knowledge keeper may have discovered it and followed it here, they wanted the knowledge it had taken. It wouldn’t let the knowledge keeper take it, so when the two got to the basement it locked the two down there with the creature, eventually though, they both found a way out before the creature had gotten them.
Eventually the visitor returned alone to the house, adding unnecessary adornments. And awfully redecorating the master's room after a while the house got fed up and tried to get the creature to attack but the creature refused.
And then that day happened, the house wanted to kill all of them, it and the creature both tried, but they had all gotten out, and they did the unforgivable, destroying the top structure of the house. It was beyond anger at this point it burned all of the individuals who had participated into its memory, it hated them more than anything it had ever hated. It wouldn’t let them get away with this, they would pay if it had anything to say about it. So the house started to work finding where each of the participants were. It would have its revenge. And when it wasn’t searching it was practicing necromancy, deep in the basement where the creature still survived. Trying its best to stitch the burnt remains of the testificates with the natural monsters who made the basement home. Soon the creature would have siblings and all would fear them.