You have just been promoted to a general in the Demon Lord's army and now you have the ability to construct a base for yourself. Many of those close to you insist that you build one and there are Gremlins, Dwarves, and many other construction-oriented mamono ready to build you your dream base. Facilities, guards, traps, the choice is yours. This does mean though that Order heroes will be coming for you due to your high rank, but perhaps you can change their minds using whatever means suit you.
The base would be large but work as a hub as a central command for other bases and it would have a landing and take off pads for flying mamonos but also comfortable for the inhabitants.
I would added steel armored manned turrets both for vehicle and anti personel also four bunkers for frontline support and a underground bomb shelter for other high rank officials who either as important as I do or more.
I'm also going to add a weapon experimentation room for both magic and machine and if I'm going to add traps I would add either a laser security system or an unconventional way and that unconventional way is using surveillance to learn more about them before going against them also I might use Stealth traps such as ambushing from hollow floors.
Facilities would include rooms for each mamono type, a large open wide shower room, a gym, a secured armory and etc but the most important of all the rooms are the information and communication room.
Guards would be different every schedule and to prevent boredom a leisure room for them and for my bodyguards I would find a corrupted order hero if there none I choose dullahans.
Edit: I've been thinking about this today but I'll also make it into a teleportation hub for other bases so if the order attacked other bases every inhabitants of other bases will teleport to the hub aka my base.
A sub base would be great I'll add a fortified island with the same defences as my normal base but act as location where water mamonos or air mamonos can take a rest or survey.
So, begining, I'll need a cliff face, preferably with at least 180 degrees of cliff. Set up walls and defences around the cliff face, with dwarves taking the stone from internal construction to speed construction.
Towers along the wall are to be equipped with explosives containing an amount of either raiju or thunderbird lightning, probably require gremlin assistance on container construction. High strength mamono should be on hand to hurl said explosives into battlefield.
Past outer wall should be buildings, either residences, barracks or leisure buildings, built in such a way as to force double or triple file march lines. Quick-deploy defensive structures should be stored in each building for rapid deployment of barricades. Request arachne for additional trap deployment. Main road leading to cliff face should be prepared with minimum three layers of walls.
Roost of flying mamono should be kept on hand in case of street fighting for deploying emergency troops into failing barricades.
Cliff face should be protected by archers, more lightning bombs, and spillways filled with either raw alraune nectar or honey bee honey. Balconies, prefferably retractable stone, but sufficiently sturdy wooden structures will be suitable, should look over outside structures. Interior halls should be filled with deployable slabs to block off attackers. Side halls should be prepared with defensive corridors.
Main hall to be suffiently grand for feasts and celebrations, with two thrones, smaller for myself, larger for potential visiting lilim. Pillars to be decorated finely, and arranged in two rows.
In emergency situations where defence has been pushed back to main hall, antrance should be sealable, requiring either mining tools or siege equipment to unblock, with escape tunnels to evacuate into mountains.
In case of hero intervention, wurms should be on notice to throw attackers into disarray.
Armouries, clinics, medicinal gardens and storage should be kept within the cliffside keep. Stonework should be overseen by dwarven masons.
Well, I'm not so big on showy, over the top facilities. And since I'm going to be living there, I'd want it to be comfortable. A nice colonial style bungalow will do me fine. With an enchanment cast over the whole place that sends any hostile intruders straight into a Silent Hill-esque spirit realm if they enter my property.
A sprawling underground base. With labyrinth that changes array of walls every half our, but as to not have mamano getting lost inside, they can leave whenever because magic. Also inside the labyrinth are DRS traps, be it saws or swinging blades. And a whole lot of puzzle rooms, only meant for the brightest to solve, so while you're puzzling if it's dig a hole or ten gold, the nice mamano behind you can prepare to capture you.