Kivotos, I will Take Away Your Future

Part 1

The Sensei of Schale.

A man with an Iron Will to aide and guide every one of his students.

A man who had endured and shared hardships with them.

The one to stand up against seemingly invincible entities who threatens Kivotos and its citizens.

An ordinary and fragile individual who cherishes every one of his students.

...Yet to end up being betrayed by the very same students he cherished and helped because of his refusal to be romantically involved with any of them.

Because another man who appeared almost at the same time as him had taken up to himself to fill out that hole in their hearts.

...

At first, one adult man, waking up in front of Nanagami Rin, had just taken office in Schale as their official Teacher.

And then another, just several days after the First Sensei's arrival, had waken up in the streets of D.U.

The two of them met on a certain incident, with the First Sensei offering help to the lost man and eventually becomes his assistant.

The two Senseis had worked together to help out and guide everyone in Kivotos.

The two of them have undone Kaiser's plans in Abydos.

They have unraveled the conspiracies behind the Eden treaty.

They even managed to prevent the disaster that would've resulted in Kivotos' destruction.

The two were an unstoppable pair in everything.

But then...

As time passes the more charismatic one becomes the shoulder to lean on by majority of the students, while the first one had been reduced to a manservant whose sole purpose is to scribble through endless piles of paperwork and enact the actual duties of SCHALE. He even gains some level of popularity among the non-student citizens, companies and organizations. Eventually, the charismatic Sensei now holds most of the authority in SCHALE and trust among the students of Kivotos, effectively making him the new leader of the Academy City.

Meanwhile, the first Sensei is now being treated as an unwanted parasite and branded as a 'criminal' throughout Kivotos. Accused of abusing his authority of swindling money and having multiple sexual relationship with his students, the First Sensei's reputation and name slowly crumbles into nothing along with the number of people he can trust drops significantly over time.

And this is happening all under the plan of the charismatic sensei.

Since the charismatic Sensei cannot beat the first Sensei in terms of battlefield directing and administrative affairs, he opted instead of appealing directly to the students by emotionally manipulating them to be his own loyal pets. He also prefers to march along with his students during battles as much as he can(but contributes nothing more than beating up one or three robot grunts and destroyed properties), allowing him to bond over more to the frontliners unlike the First Sensei who is now relegated to oversee an operation at the safety of a well-guarded command post(that is the key to their successful missions). In addition, his muscular physique combined with a thin layer of Kindness and being a gentlemen on the surface allowed him to worm his way into the student's hearts and mind, giving him a 'perfect man' image to the majority of Kivotos.

The students who were once affectionate to the First Sensei now becomes hostile and cruel towards him, in design of the charismatic Sensei. Spreading out false rumors and encouraging the students to physically hurt him as punishment for being 'lazy' or anything he can think of, the charismatic Sensei relishes the sight of the first Sensei bullied by his own cherished students whilst he's burying all of the crimes he actually did.