Below ground
As the upper portion of the castle is expected to provide event space, food space, and so on, it will be hooked into the existing utility structure. This extends into the basement as well. A small office space will be implemented to keep people from nosing around too much until the shelter space is needed. The rest of the area will be handwaved as storage for the time being.

Alucard will have personally overseen the removal of all building material excluding essential infrastructure related to Thorne to ensure no trace of their magic remains in the space. That essential infrastructure will have been scrubbed with a combination of literal fire to burn holes through connective magical tissue, physically chippings things out, and otherwise interrupting anything where physical removal would threaten greater safety. In doing so, the overall aesthetic of the dungeon will be decidedly not a dungeon. Instead, four blocks aligned long the cardinal points will be placed into the space, creating dorms. Arches, columns, and new brick work will serve to beautify ths space, with a particular emphasis on geometric designs and warm jewel tones to create a more inviting atmosphere. Pillars and columns will also be present to provide extra support, and will feature creative flourishes.

Longer sections of wall will feature murals and mosaics that range from landscapes to trompe-l'œil to blank spaces that are meant to be available to residents as a form of stress release if the spaces are activated. Each area will house approx. 500 people. The rooms can house either two or four people at a time.

Lighting is essential. Magic is used to modify existing electrical lighting options to run through a 24 hour cycle, ensuring that anyone underground at least feels like they are at the surface. Daylight hours will run as close to daylight as possible. Night hours will feature a different glow.

Each dorm block has the same set of amenities. The areas with designated rooms are more open with airflow and space (within reason for an underground space. The amenities are as follows:

1 centrally located security point, which is in constant communication with the other four throughout. A main point is also included in the north wing.

Four communal bathrooms, enough said.

Four communal kitchens. These spaces include small cooking spaces, similar to irori, with ventilation provided to address fires. A pantry space is attached, with assigned cabinets for each dorm room. The cabinets rely on magic (finger print and a PIN number) to open. There are additional communal staples available, and the pantry space itself relies on magic to extend the shelf life of the food within. The kitchens include some recreactional material including books and art supplies.

One green house area with UV lights. In addition to plants provided for touching grass, crops can be grown in the area as well

One medical bay with the ability to perform light surgeries if need be; the west block will have advanced equipment. The same magic used on the pantries will be applied here in order to extend the shelf life of medicines.

Two recreation areas with board games, a library, pool table, comfy sofas, art making spaces (with supplies), and [other things?] to help time go by.