Picture this: there is a high fantasy world with a majority of humans, but in recent times there have been other, monster based species gaining traction (i.e werewolves, naga, harpies). In this current environment, we have our villain, a Dracula-esque, supernatural corrupt noble who has magical power at their fingertips and essentially wants to build a base of power.
Now if your first thought from my question was Castlevania, you'd be correct. I always wondered how exactly so many variety of creatures came under Dracula's castle, and why they were willing to work together, at least long enough to impede the hero, rather than getting at each other's throats due to cultural differences. However, my goal isn't to ape Castlevania entirely, as the focal figure wouldn't be Dracula, nor share his same motivations or even species.
As far as magical limitations go in this world I have, mana is best produced through living beings, though any solid object can contain it. The more magic cast by volume, the more mana it depletes, so large scale magic either requires a lot of people, an artifact of densely packed magic or someone of massive size. Draining magic through the same target over a longer period of time grants more magic than draining them to death, unless there needs to be a lot of magic in a very short time (e.g holding open a dimensional rift).
Assume that this figure is a relatively powerful humanoid but not human. They are long lived enough to know a variety of spells, have a hardier body than the average mage, relatively attractive and have plenty of charisma, and does not need to worry about aging. If not killed correctly they will revive in a short time or will even reincarnate. A combination of pragmatism and xenophilia prevents them from being downright heartless, but they are willing to stir any level of mayhem to get what they want, whether it is new minions or to assess the character of anyone they deem interesting or a threat.
As for the castle, assume that it is essentially a 'living being' that absorbs magic from its residents in turn for offering protection in order to maintain itself.
What would the villain need to both create this castle and provide for their minions in order to follow them and work to further expand said villain's influence?
EDIT: to narrow the focus so I have an objective question, I can add the following details:
- The castle itself should initially be large enough to house about 200 humanoids, with room to expand. The villain will naturally prefer a high but not too high spot, like a low mountain, cliffside, or large enough hill with good moonlight.
- The castle walls should be able to withstand most high level spells, so in case an angry calvary notices and attempts to attack, they would not have any luck.
- The castle should look appropriately spooky and strange, especially at night. Aside from the gothic tones from Castlevania, I'm willing to experiment with other styles, like how Great Zimbabwe was built, or even a blending of said styles.
- The castle should be able to house a variety of environments for humanoids. Rooms can be lined with magic to mimic environments that aren't possible in the local area (like deserts or areas of extreme cold).
- Not refined yet on my end, but there are metals that store elemental energy (fire, water, earth, wind, light and darkness; first four more common than the last two) better than known metals here. They can be blended, with certain exceptions that oppose each other (light and darkness, fire and water).
- A minor side note: non-magic technology is closer to early 1900s America, and indoor plumbing would be a possibility for this castle, cities, and rural nobility.
- Just like Castlevania, this castle is a 'creature of chaos'--i.e, living being that can change itself. Unlike Castlevania, it did/does not start off at castle size, buildings and/or materials are needed to be added before it can maintain its size and change it however it wants. For this exercise lets say it starts off the size of a two story house, with a shrine that holds the creature's 'heart'.
I recognize that some of these aren't realistically possible, but the hero of this story studies magic and how artifacts are put together, so I would like something that could be consistent and more than 'the castle was magicked into existence'. What materials should the villain get, and who would they need cooperation from?