Rex Crozzo was not always an introverted game-obsessed man.

No, he was once a playful extrovert that enjoyed hanging out with people and dragging them to have fun. Like a certain eyepatch-wearing girl that was his best friend and he had met when they were just 2 years old.

After all, He and Kiana were 2 years younger than Bianka and Reve.

(This is merely speculation as the 2nd eruption happens during 2000 AD with Cecilia dying in canon. With Otto cloning Real Kiana to make K-423 a.k.a Tuna. This makes it that Bianka is 18 by the year 2016 and 19 in 2017.)

It all changed in the first year of middle school. He was slowly ignored by Kiana and forgotten. They stopped hanging out together with Kiana even gossiping things about him to some of her friends.

His middle school debut was horrible. Basically alone and having no friends in his class, he started playing games and gained an online friend instead.

It staved off the loneliness as he never saw Kiana much except for the occasional dinner with the Kaslanas or when Kiana was forced to spend time with him whenever Bianka kidnapped his older brother for a mission.

The only one he was close to personally was Yae Rin, Reinhardt's apprentice. Well, she does train with him whenever Rein decided to have fun and flirt with the lesbian duo.

Poor guy, chasing an unrequited love.

Back to his life.

It all changed when he entered his second year. Some nasty rumors popped up and he started to get bullied. It was not much at first, just some name-calling that he ignored.

But then, an incident about the Kendo club happened and just because of his bad luck of being near the area, he was seen as the culprit.

After all, it was the word of two popular female students against the introverted weirdo.

It kept on going until the last month of his 2nd year of middle school. Where it was revealed that it was someone else he did it.

He did not really mind and went back to his own. The straw that broke the camel's back was somewhere near their graduation.

He sent more than half of his classmates to the hospital and made them miss the graduation ceremony.

His older cousins fought tooth and nail to protect him and he was forever grateful for them.

So for his high school debut. He entered St. Freya's modular system, preferring to have his own schedule and be alone.

Ever since the bullying he received from Kiana or from the others, he started to hate people that were not family or friends.

He mostly stayed in his room or the house whenever he was not busy or in missions. He had evolved to a semi-NEET. he had transcended mere mortals.

That did not stop Theresa from sending him out in co-op missions that he makes sure to finish. He always gets partnered up with that girl, Bronya for some reason.

Well, they do make a great duo.

Her deadly long-range accuracy partnered with his close to mid-range expertise was great. He trusted her with his life.

He could safely say that she is one of the few people he is fine to be around

The young man was currently suiting up for a mission. 

His Auntie Theresa had sent him the details for a new mission to hunt down and destroy an emperor-class Honkai Beast. Normally, a Schicksal knight would need to be A-rank or higher to fight one but he was a special case. 

He might be a knight but he was a Crozzo hunter first and foremost. 

He might be the weakest of the Crozzo trio composed of him, Reve, and Reinhard, but he was more than enough. Putting on a black open trench coat with a cross symbol on the back over a roman numeral number 2. He completed his outfit and made sure the fur-lining was secure. 

"It's been a while since I went hunting." Taking out a specially modified sword. He ripped it off of Red queen and named it Maxwell's Demon. He named it after that experiment. He also has an ice-element replica of the judgment of Shamash called Hati Skoll separated into a pair of revolvers.

The Crozzo family hunters have a specific ranking on their own

Beginner

Experienced

Veteran

Master

Master-rank Crozzo hunters, also known as Slayers, are comparable to S-rank Valkyries.

Veteran-rank hunters are comparable to A-rank Valkyries. 

Experienced hunters are comparable to B-rankers and

Beginner hunters are comparable to C-rankers. 

To move up a rank there are several criteria needed such as:

Slaying more than a hundred Honkai Beast

Completing several higher-ranked missions than theirs

Passing a promotion exam. 

Currently, Rex Crozzo is a Veteran-ranker with his pseudo-divine key but without them, his destructive capability is enough to rank him as probationary Veteran-class.

His cousin, Reve (Bianka's goto partner if Rita is not available) is a Master-class hunter and is able to take out hordes of Honkai beasts by himself without breaking a sweat. 

Reinhardt, on the other hand, is a probationary Master-rank not because he was weaker than Reve, but because he had no reason to increase his rank. That man can effortlessly wipe out a city filled with Honkai zombies in less than 12 hours if he put his mind to it. Sadly he was too focused on womanizing or spoiling with his apprentice. 

Yae Rin, Yae Sakura's little sister, and Reinhardt's apprentice, is currently an experienced hunter. She is often stuck with dealing with Reinhardt's antics.

Rex put on a pair of glasses and an image of Theresa Apocalypse appeared.

"Hey, Rex! You have a mission. Head to Silent Hill and investigate the area. Good luck, the files will arrive soon." Fixing the glasses on his head, one will be able to mistake him with Fu Hua if not for the dark hair, eyes, and the spiky pompadour he had on. It was cool, don't judge him. 

Getting off his room, he arrived just in time to see that Reve has finally gotten home... is that Bianka clinging to him like a Koala. 

"What happened?" 

"I don't know..." Reve said while letting one of the strongest Valkyrie of their generation cling onto him like she weighed nothing. 

"huh, neat. I'm heading out for a mission." Rex said.

"Hey, Rex!" Rin greeted with a smile while dressed in casual clothes and one of his old training jackets. 

"Hey, Rin." 

"Wat! Rex! You forgot your meal!" Reinhardt Crozzo dressed in a white shirt with the sleeves rolled to his elbows and a pink frilly apron shouted as he ran in while carrying a lunch box. "Don't forget to eat a meal and rehydrate." 

"I won't," He said with a smile as he walked out while carrying the Bento with him. 

[===]

On an empty room filled with a lot of HOMU dolls a familiar form of a 14-year-old girl with gray hair hummed as she bit on a pocket stick and played on her computer. 

The girl looked to the side and stared at a simple trench coat with a Gemini symbol under a cross and on the table near it is a picture of Rex Crozzo revving Maxwell's demon while a blank-faced Bronya had her project Bunny beside her. 

"Come on, Bratnya!" 

"I'm on my way Kiana Idiotka." The girl said as she took her bag and walked away.