Hell District Defenses:

Anti Energy Protocol 7:  Underneath chaya nation, the Hell district which is home to ninsun  unknown to the queen has been renovated. One such renovation is the Anti Energy Protocol or Protocol 7.   This protocol activates what is essentially hundreds of doors bolts, and locks which lockdown every tiny entrance to the underground country.  These doors have been encrypted with knowledge ninsun herself has gotten from everyone of her other programs that she runs. Meaning they have a natural Anti-Energy property which allows them to in situations of need to literally if needed keep out high 0-tier combatants as long as the sub-energy source which is running within the mechanized city is actually processing and running at full capacity. Meaning that these doors which are made of a combination of seki-seki like materials and unknown metal ore can essentially if needed hold off assaults from 0 tiered individuals or nuclear blasts for up to 24 hours.  Because of the fact that these doors afterwards are programmed to  reset themselves, in which time the whole cities secondary system of doors kick in.  Which is Defense Order 2.

Defense Order 2:  If Anti Energy Protocol seven fails, then every single door and every single passage in the great underground city is made to automatically slide shut, thick reinforced doors which are of super-solid  qualities. these doors have been essentially made  to be able to block some pretty hefty damage, and  will not unlock until the command prompt which is running all of them actually is resent. Meaning that the second 24 hours have passed from the activation of Anti Energy Protocol 7, then  essentially the entire Hell District itself goes on direct lock-down, making it so that  to get through the tiers  one would have to bust through each door each barrier directly,  and because of the cities centralized nature,  the defenses naturally get stronger the further into the city one gets.  As such the tiers themselves or “Levels” of defense that are present will eventually get stronger and stronger.

A Block:  A block is the outermost district of the hell district, it is essentially the gate-way into the city. Making it so that to get through the city one must crack the outer defense of A-block to even get to the city itself in the first place. As A block itself has some features which itself are built in so that the city cannot be easily breached without some sort of fight or atleast without some serious kinds of effort present.

Anti-Warp Defenses:  Using Arcane Knowledge, the A block has defenses which stop individuals from teleporting into it, meaning if an individual wants to get through into A block, they must enter it  by busting down through the front door,  quite literally.  This is run by one of the cities three cores, which are used to power immense amounts of technological advances which are easily perceived throughout the city.  This particular defense however is activated after A block has been pretty much broken into, making it so that  After entering A block a trespasser seeking to enter or exit must do so on foot.  This Defense is made essentially because of the fact that A- Block is a border land of sorts, it doesn’t have multiple processes to it, but at the same time this defense is made specifically for keeping people out.

Spatial Collapse:  A Block can at the price of it vanishing, actually in times of last resort collapse the space that its in,  I.E because of the demon magic circulating through ley lines that are present it becomes possible for the literal dimensional space to be locked down and changed, essentially making it so that  one would have to find the control center in A block and destroy it before they would be able to exit A block.  And even then it would take time for a person to be able to fight their way out of A block  seeing as they would have to break down the doors and the  barriers which are formed around the city itself naturally.

B block:

C block:

D block: