Eren walked inside the dark cabins, guided by a mysterious ominous feminine voice that did not ring a bell. And as he walked, he could hear narrations coming from the same person.

"It has been long since I gave up the search for the spell of youth. Until I Found you. Eren Jaeger."

The voice echoed in the dark hallways.
Eren was sure of One thing. The hallways he was walking in were not usually dark in the middle of the day.

"Who are you?! What do you mean?!" Eren asked, desperate for answers.

The eeriness of the environment around him kept feeling darker and darker, which mean he was going in the right way.

Then all of a sudden, the environment around young Eren was dark and silent, before he felt like he was being watched, but at the moment he did not feel anything. There was no light source near Eren for him to see.
The corridor was darken than the sky at night, lit with the pale moonlight.
Only a big dark door was visible in the darkness as Eren stood in front of it.

Eren felt the urge to open the door and walk through it and so he did. And as he opened the door, Eren started to regain the dark vibes from before. Eren closed the door behind him without even sensing his body doing so or even noticing it. His body was moving on its own while his mind was focusing on following the voice.

Then he started to feel as if he was being touched by a demonic entity, even though there was nothing to be seen.

A tall, creepy, shadowy, cloaked figure stood in front of Eren. The figure is tall enough that it towers over Bertholdt himself.
The figure was surrounded by a dark aura that made it even more creepier.

Eren's eyes did not avert from the supposed face underneath the dark hood as he was aware that the figure was eyeing him, staring at his face with an evil gaze.

The entire room was silent for a minute until Eren spoke these following words:

The voice then laughed. A feminine laugh with a tint of demonic echoing followed.

The laugh was coming from the dark entity in front of Eren but he was hearing it from the entire room, surrounding the little boy.

"You wouldn't want to try that, my dear. The only thing you should be worried about is whether or not you would survive this day." The demonic voice stated, not moving an inch,

"Who are you?!" Eren asked with a slight bit of fear coming from his mouth.

"I am your worst nightmare, my boy. I am Xenarys. The succubus demon from the underworld. And I need your blood."

"What for?" Eren asked.

"You have been struck by lightning from a red cloud, if I am correct. That cloud aged you backwards, turning you into an infant. Your Blood contains the liquid form of the spell casted upon you. It is infused with your red interstitial fluid. I need it."

"I'm not gonna give you my blood!" Eren shouted at the dark entity known as Xenarys.

"I am planning to take it from you anyway."

Suddenly, large dark tentacles emerged from both Xenarys' body and from under the ground and wrapped themselves around Eren and lifted his tiny body a few feet off the ground.
Xenaris approached Eren.
Then some form of living goo started to emerge from Xenarys' body and merged itself with Eren's body through a symbiotic relationship, connecting itself to his skin, organs, cells and even his own blood and mind.
Eren started to feel his life being literally sucked out of him.

But then, just in the nick of time, the door was kicked open. Two people ran at the succubus and cut off the tentacles that were wrapped around Eren and caught him when he was falling.

It was Mikasa and Annie. They sprinted with Eren out of the room as Annie carried Eren with Mikasa in the lead.

Xenarys gave chase. She ran after the two girls with a blink of an eye, trying desperately to catch Eren by using her tentacles to reach them.

Finally the two girls run out of the cabins and straight towards the training area where the rest are located, but to their horror, everyone was on the ground, wounded and bruised. Some of them were knocked out while the others were crying for help.

The sky was dark. No sun or light in the sky was visible. The three wondered why the sudden change in time. But then they realized that the sky has been covered with some form of dark magic, tainting it and preventing the daylight from reaching the world.

Dozens of soldiers were surrounding the entire perimeter. They were 7 foot tall, armored creatures that possessed a humanoid shape but were wearing dark and strong body armor that covers their entire body, including their faces.
These soldiers were everywhere. They were in the training areas, near the soldiers they beaten up, some of them emerged in the cabins. Others were in the mess halls. Some of them were forming an entourage to Xenarys.

Xenarys then decided to take off her cloak and reveal what she really looked like.

Her physical body was breathtakingly beautiful. She had all the features that any man wants and all women dream to have. She had all the amazing natural curves, the big butt, the big rack, and especially she had a sexy facial structure.
Her eyes were red and she had sharp vampire fangs sticking out of her mouth. Her long hair was dark red and voluminous.
She wears a leather outfit that covers her chest area but keeps the belly button area entirely visible. She also wears leather shorts that reaches her thighs that are connected to leg nets.

Her huge bat wings are very visible to the naked eye. They are a sign that she is a true demon.

She also wears the demon shoes below:

She also has a whip that is holstered on her side and a sword on her back.

She wears red gloves on her hands that reaches her wrists.

Eren and his friends knew they were in deep trouble.