This is the closest depiction of the fort I can find, with the top image being the exterior of the fort as a covering to prevent Demons from dying from the Sun. The bottom image is the interior of the fort, as it looks like an ancient Japanese City.
NOTE: This page has a soundtrack and the video should be played when reading this. You can try matching the time stamps to correct points of the video to make it more accurate.
(0:00) We see the big monstrous Fort Wagner, which is now a Japanese styling fortification instead of the old beach and earthwork fortification. We also see four daytime guard Demons on their posts as they have conquered the sun.
(0:05) The camera then goes into the interior of the fort, going through the massive rooms full of many vital Demon equipment, and many Demonic creatures are shown, along with a big rally place in the middle of the fort.
(0:10) We see Yotsuyahi gather the Demons towards the meeting place, as he prepares the assignments for the other Kizuki and Demons for tonight. He speaks towards the Devils.
"I feel like it is time to feast! Our Demonic Fort Commander has wanted us to kill as much as 35 Humans this night, and I want you to accomplish that. Do you want a good meal? Let's get it done then!"
(0:18) The Demons chant and agree with him.
"YES!"
(0:21) Yuki sees them love the promise and she even likes Yotsuyahi's reward.
"That reward is nice, mmmm I can't wait for some good food and more humans!"
Yotsuyahi decides to leave the podium and go to somewhere else in the Fort, while Yuki goes toward her puppet cage.
(0:30) We see Yuki open the door to the puppet cage (or should I say Slave Cells) to where we see 20 tamed Humans that will work under her order due to her BDA to make people be under her control.
(0:35) Yuki commands her Slaves and orders them to prepare to kidnap meatier Humans to eat.
"My children, I want you to bring me some food to eat! I want a good meal please from you in the outside world."
The possessed respond back.
"Yes, my wife and love!❤️😍💕"
(0:42) We then see the Demonic Creatures go around the Fort doing their things while we see some exit the Fort to do the mission. The Montser of a Fort is active as we see a lot of movement.
(0:50) The camera then goes towards Yotsuyahi in his room, seeing his intrusive thoughts on Humans.
"I want to be on Muzan's side and win the war! Humans don't live forever, but we Demons do unlike my mom and dad."
Yotsuyahi says that as we see a past memory of him being transformed into a Demon by Muzan Kibutsuji.
(1:04) Yuki is now shown as we see her backstory, how she was a very beautiful person loved by members of the village. We also see her Demon transformation and we hear her thoughts on Humans.
"They are ugly, never better in beauty other than me. I hope they won't advance above me as I am the only perfect being!"
(1:15) A camera now shows the exterior of the monstrous Morris Island Fort as we see Demons emerge from all entrances as they make it towards South Carolina land near Charleston, SC.
(1:21) We see the Demonic Figures cross the bodies of water to make it onto SC land.
(1:29) We then see patrolling Union Soldiers spot a Demon and engage in a gunfight and kill one of the Devils, but they spot more and request more patrol units to be near the Fort in the oncoming wave. A scream is heard, and Civilians are now seen defending themselves along with Military Troops now arriving to deal with the Demons, along with Civilians.
(1:42) The scene shifts to daytime 12 hours later and the casualties are revealed.
(1:48) A paper is written out, writing the casualties. It reads:
"Casualties on the night of July 16, 1913:
12 Warriors Dead.
6 Soldiers Missing.
23 Yankees Wounded.
9 Civilians Dead.
7 Citizens Missing.
37 Regulars Injured.
Total Dead:
21
Total Missing:
15
Total Injured:
60
Overall Casualties for the night of July 16, 1913:
96"
(1:55) And cut, end of the chapter!