Lesson 1: The Intruder

People fear what they do not understand.

A straightforward phrase. Nanagami Rin understood it clearly. As a younger student, before joining the General Student Council, she had often found herself dreading exams where her grasp of a subject was tenuous.

Today, however, her understanding of the idiom was challenged, much to her despair.

It was fear, she realized, where her knowledge was pedestrian at best.

The past few weeks had been harrowing, growing increasingly taxing with each day that the President remained missing and with each new emergency that popped up in the wake of losing control of Sanctum Tower. Small at first, Rin could feel a dark and ravenous fear growing in the corners of her mind as the situation spiraled further and further out of her control and the promised Sensei remained nowhere to be found. The fear that this would never be fixed, that there was no Sensei, that Kivotos was ultimately doomed, and that her dear friend would never return.

But even this fear, her hidden insecurities and doubts, and her childhood apprehension of exams all paled in comparison to what she was feeling now.

Rin gasped, her breath catching in her throat.

Her skin prickled as a chill ran up her spine.

A knot formed in the pit of her stomach.

Against her will, she began to tremble.

Every instinct in the bespectacled student's body told her to flee, to get as far as way as possible, and yet she stood transfixed; unable to move as the fear she harbored broke free, became terror and rooted her at the entrance to her office.

There was a stranger inside.

The blue uniform she wore and school bag she carried identified the stranger as a student, but from which academy Rin could not tell. Pale and thin fingers rested upon the windows of Rin's office as the stranger stared outside towards a city sliding ever further into chaos. Despite the distance between them, Rin could feel something disturbing about this person invading her workspace. There was something wrong about their presence. Something almost alien -no, inhuman- about them.

And she had no halo.

A student with no halo.

Rin stared at the impossible person standing in her office and felt herself begin to hyperventilate -something that had never happened before- as her mind tried to grapple with the incongruous sight before her. A student without a halo. Something incomprehensible, someone that by all rights should not -could not!- exist and Rin had no choice but to face the reality that her understanding of the fear of the unknown was woefully inadequate. She tried to speak, but the words caught in her throat and the only sound she could make was a strangled squeak of fright. The shame lasted for only a second as the strange student must have noticed her presence then, turning around to face Rin at that moment.

She had delicate features framed by light blue hair styled in a messy and haphazard bob-cut.

Eyes the color of blood fixed Rin with an icy, emotionless gaze and a soft voice sprung forth from pallid lips.

"Who are you?" the intruder asked in a voice as frigid as her gaze.

Nanagami Rin, Vice-President and Chief Administrative Officer of Kivotos' General Student Council, did the only thing she could.

She fainted.

"Rin! Wake up, Rin!"

Recognition and the sensation of being shaken slowly pulled Rin out of unconsciousness and she groggily took stock of her surroundings. She was in her office and Ayumu, her colleague, friend, and secretary, leaned over her with an expression of relief on her face. Her green eyes looked damp, as if the perpetually timid girl had been struggling to hold back tears and failing. Surrounding them was a haphazard mess of papers, binders, and envelopes. Ayumu must have dropped them when she came in and found her unconscious.

Found her unconscious?

Rin bolted upright as the memories came flooding back and she roughly grasped the taller blonde by the shoulders. The secretary grimaced in pain, her black wings twitching in response to the pressure.

"Ow, Rin, you're hurting me…" Ayumu mewled pitifully.

"Ayumu, where is she?" she hissed.

"Huh?" came the confused reply. "The President? We still haven't found her, Rin. You know that."

Rin wanted to scream but somehow managed to restrain herself. "Not her. The girl. The intruder."

The bewildered expression on Ayumu's face was all the answer she needed. She looked towards the window again and found no one there. The student that should not exist was gone. A thousand scenarios flitted through Rin's mind as she stood up despite Ayumu's protests. Was it a hallucination? A dream? No, their meeting had felt too real. It couldn't have been a dream. That Ayumu had found her unconscious surely confirmed that her strange visitor had been real. But then… What would the President do? No, no time for that train of thought, she admonished herself. She had to act quickly, decisively. She had to keep this a secret, but she also needed the intruder found NOW. Coming to a decision, the dark-haired girl gritted her teeth as she realized she was going to get hell from both Kaya and Aoi for this. And yet, what choice did she have? None. She would have to deal with the fallout later. Rin strode to her desk and activated the alarm below it. She heard Ayumu gasp.

"Attention all GSC personnel, this is Vice-President Nanagami speaking," she activated the building's PA system and spoke, willing herself to calm down and speak professionally. "There is an intruder on the premises. On my authority, GSC HQ is to be placed under lockdown. Until further notice no one enters, no one leaves. Security Forces, locate and isolate the intruder immediately. Light blue hair, red eyes, and blue uniform. Approximately 150cm tall. Bring her in *unharmed*," she stressed the word, "to Detention Room 1. I'm on my way."

Finishing her address, Rin turned off the PA system and grabbed an earpiece from one of her desk drawers. After quickly putting it, she finally allowed herself to let loose an exhausted sigh as she removed her glasses and rubbed her eyes. Reactions, however, were immediate and the moment of respite was short-lived.

Her earpiece communications instantly became active as GSC HQ Security Forces contacted each other and the control room in search of the intruder.

She received an incoming call from Kaya on her smartphone. Rin pressed the touchscreen button to refuse the call and turned off the phone.

"Rin, what are you doing?!" Ayumu all but wailed as she raced over. She was on the verge of crying once again. "We have academy representatives in the building! We're going to be in so much trouble!"

Rin ignored the outburst and stepped from behind the desk and towards the door. She waved for Ayumu to follow her outside, and the confused, teary blonde seemed to get even more distraught at that, her wings trembling miserably.

"But the paperwork…" Ayumu sobbed at the disorganized mess on the floor.

"Unimportant," Rin interrupted her as she took her Desert Eagle out of its holster and quickly checked it. Satisfied, she grabbed a hair tie from her uniform pocket and quickly tied up her hair in a ponytail. "Ayumu, get your gun. We're joining the search."

"What?" Ayumu squeaked, feeling increasingly confused with every passing second. "Rin, wait!"

Rin did not wait.

The search was unexpectedly brief. It was almost as if the intruder had made no effort to hide or escape at all. Still, Rin mentally thanked whatever lucky star had decided to finally have mercy on her.

It was only a scant few minutes before the Security Forces informed her that they had successfully found the intruder and apprehended her. Because of the nervous and fearful voice on the other of the comms, Rin was even certain that they had found the correct person. She headed towards Detention Room 1 with Ayumu following closely behind, still bewildered but no longer on the verge of crying. They made their way through the corridors of GSC HQ quickly even with SF guards patrolling and on high alert.

Ayumu, who had remained quiet as they made their way towards the Detention Rooms, finally decided to break her silence. "Rin, what's going on? Did someone really break into your office?"

Rin nodded affirmatively as she replied. "Right before you arrived, I imagine."

"Who was it? Was it someone from the Pandemonium Society? Their letters have been getting…" Ayumu trailed off and did not finish her sentence, tittering nervously instead.

"No," Rin replied tersely, "Not anyone from Kivotos."

"Not from Kivotos?"

Ayumu's question was left hanging as they arrived to find white uniformed SF guards peering curiously through Detention Room #1's door pane and whispering to each other in hushed tones.

"What the hell did I get myself into now…"

"Is she a ghost? Am I going to be cursed?"

"Do you think it's contagious?"

"It's a zombie! Kivotos is doomed!"

"I'm telling you it's an alien! Kivotos Paranormal said aliens kidnapped the President and now she's here for the rest of us!"

Rin cleared her throat loudly and silence immediately fell upon the guards as they turned around and saluted awkwardly, eyes repeatedly darting towards the door.

"Ma'am! Vice-President, we found, uh… her," the one in charge, a captain, informed her lamely, eyes still darting nervously towards the door.

"Thank you, Captain, that will be all. Ayumu and I will take it from here," Rin nodded at the captain. "Please let the Security Forces know that the emergency is over. You may leave."

The entire five girl squad of white uniformed SF guards let out collective a sigh of relief as they shuffled away from the door to let Rin pass.

Opening the door, she was relieved to see that they had indeed found the intruder. She was less relieved to see that those inscrutable red eyes looked at her with the same dismissive coldness as before. Whoever she was, she did not care at all that she had been caught. Rin opened her mouth to speak but could not get a word out before she was interrupted by a loud crashing sound from behind her.

Ayumu had fainted.

Not that I can blame her, Rin thought to herself with no small amount of chagrin. "Please take her to the infirmary," she addressed the flabbergasted guards standing still in the corridor. They remained frozen in shock for only a second before nearly falling over themselves to carry Ayumu and beat a hasty retreat.

And now Rin was alone with a person who should not exist.

Suddenly, she felt as if this was an immensely stupid thing to do, but she quashed those thoughts as she took a seat across from the intruder-now-detainee and cleared her throat.

"I have some important questions for you. Please answer honestly and you will be free to leave."

The only reaction she got was a blink.

"Who are you?" Rin asked, returning the stranger's earlier question back at her.

"Ayanami Rei."

The reply came quickly, curtly, and with no attempt to dissemble. It was enough to shock Rin off balance and she cleared her throat to begin once more.

"Where are you from?"

"Tokyo-3."

Another fast reply and without the slightest hint of dishonesty. Rin could not help but feel confused. She had never heard of that district before. Then again, there were thousands upon thousands of districts, and she was not exactly familiar with all of the smaller academies. Shaking her head, she pressed on with a different question.

"What is your academy?"

"Tokyo-3 First Municipal Junior High School, Class 2-A."

Too much to hope that she belonged to a large academy or some well-known branch. The dark-haired student grit her teeth. These senseless answers were getting her nowhere and weeks of relentless stress were making her patience run out faster than normal. She resolved instead to ask the question that was burning in the back of her mind.

"What are you?"

Silence.

"What are you?" Rin repeated again this time more forcefully. She kept her eyes on the intruder's, Rei's, face trying to detect any sign of dishonesty. It was an experience akin to trying to discern the emotional state of a rock.

"That information is confidential. You do not have the appropriate security clearance."

Rin could only blink at that reply. "What?"

Silence again and Rin could feel an explosive anger well up within her as she stood up forcefully and slammed her palm into the table.

"Listen, you-!"

"Where am I?"

Rin sputtered as her anger died on her lips. Rei had apparently decided that it was her turn to ask questions.

"Where am I?" the albino girl repeated in the same exact tone as before.

Rin glared at the younger girl as she took her seat again and crossed her arms. Her anger momentarily dissipated, and, for lack of a better idea, she answered, "This is Kivotos, the Academy City. Specifically, this is the General Student Council HQ."

It was then that Rin noticed the barest hint of emotion flit through the intruder's face.

A blink. A slight creasing of her eyebrows. The faintest hint of tension at the jaw.

Confusion? Anger? Fear? Frustration? Rin couldn't tell for certain. It was all too brief and far too muted. She had heard other GSC staffers refer to her as harsh and emotionless behind her back, but she was certain for a fact that she was never this inscrutable.

"This is not Tokyo-3?"

"I have never heard of Tokyo-3 before," Rin answered plainly.

Rei gave a slight nod at her answer.

And then she stood up.

And then she walked towards the door.

And then, without turning to face the stunned older girl behind her, Rei opened the door and brazenly stepped outside.

"Goodbye."

The soft click of the door settling in its frame was deafening as Rin stared and gaped, completely dumbfounded.

"Wait!"

Rei did not wait.

Lesson 1: End

What did we learn today, class?

Yes, that's correct!

Zombies don't exist.

Join us again next time for Lesson 2: The Teacher. We'll have: more talking, more fainting and more… service? I don't know about that.

Don't be late!

AN: After many years of inactivity, I recently stumbled upon various BA crossover fics where Sensei is replaced by another character. Some are even hosted on this site. Anyways, I really enjoyed them and started giving thought to how I would handle such a crossover. The result was a small snippet that I posted in a certain forum. Despite that, getting the idea out of my system was not enough and I ended up mulling it over a bit more and expanding it out to chapter length. I'm still not sure if this idea has legs to it, but I would like to go as far as I can and find out. Hopefully, it'll be a fun journey. -Kero