The Martial Unity

The man didn't have so much as a hint of hair on his head, yet his eyebrows, mustache, and beard were long and overflowing. His visage was aged and elderly. His eyes seemed to radiate a depth that Prince Raijun was unable to fathom.
They regarded Prince Raijun without a hint of reverence towards the symbol of the Royal Family.
"Sir Armstrong," Prince Raijun bowed. "It is an honor to be in the presence of the first sword of the Kandrian Empire."
"Speak."
The man's voice rumbled, possessing an inhuman depth.
"...I would like to request you to fight as my champion in a Martial duel that I have accepted."
The Gatekeeper's eyes narrowed.
"No."
He turned back, returning to the lake with heavy steps.
"Please, Sir Armstrong!"
THUD
"Help me!"
THUD
"Help me win!"
THUD
"DEFEAT THE VOID PRINCE AND MAKE ME EMPEROR!"
The man froze.
He turned around slowly.
His powerful gaze pinned the Martial Prince in place.
"... Tell me more."
A wide smile of jubilation emerged on Prince Raijun.
Unfortunately for him, the news of what happened that day could not be contained. He was not the only one who had eyed the Gatekeeper.
Rui sat in a room, isolated from everybody and everything. He had reserved a space of absolute silence to condition his mind for combat to ensure that he was at his absolute peak going into the battle.
CLACK
The door opened, breaking his focus.
"This better be important."
His words were intense.
The messenger of the Martial Union flinched. "Y-Your Highness, it's Their Masteries. They have requested your presence immediately. They said it's urgent."
Rui frowned, immediately getting up.
He knew that the Martial Masters in his orbit would not call him for something stupid and meaningless. Whatever it was, it was mostly likely something that he definitely would want to know.
"Take me to them now."
It wasn't long before Rui found himself before Master Ceeran, Zentra, Vericita, and Aronian.
He glanced around at them, immediately noting the tension in the air.
It prickled at the skin.
There was a distinct gloom that lingered in the air.
"...What's going on?"
"...Please have a seat, Your Highness."
Rui frowned, taking a seat before them. "What's this about?"
"You must find a way to terminate your Martial duel with Prince Raijun, Rui," Headmaster Aronian heaved a sigh.
"What?" Rui narrowed his eyes. "Why?!"
"Because we just received news about who Prince Raijun has chosen as his
champion." Master Zentra calmly remarked.
"...And?" Rui raised an eyebrow. "What is this, a drama? Just spit it out."
Master Ceeran grew grave. "His champion is...is none other than the Gatekeeper himself."
The name lingered in the air like an incantation.
Its very utterance weighed on them.
"...Who?" Rui tilted his head.
PAT
Master Vericita patted him on the head with affectionate concern. "The Gatekeeper, Sir Armstrong, the first Squire and Senior of the Kandrian Empire. Centuries ago, the strongest Martial Artist in all of Kandria before the advent of the Master Realm. A legend. His name was known throughout the Kandrian Empire when I was but a young girl but has been forgotten over the centuries as Martial Art progressed far beyond the Senior Realm."
Rui could feel the respect and admiration in her voice for who was supposed to be a Martial Senior. And not without reason, either. If even half of what she said was true, then her reaction was understandable.
"...Is that why I've never heard of him?"
Master Ceeran snorted, amused. "No, in your case, you're just too self-absorbed
in your Martial Path to care to find out."
Rui regarded that with a light shrug, unable to deny it.
"So..." Rui turned around to each of them. "Old Senior veteran is my opponent, got it. What's with all the gloom?"
"He is strong, Your Highness," Master Zentra calmly remarked. "The strongest."
"There is no one who has cultivated the Martial Body as much as he has, Rui," Headmaster Aronian gently informed Rui.
Rui narrowed his eyes.
"Do you recall when I told you that the highest three grades of the Senior Realm are wider?" Master Ceeran remarked.
"... Yeah," Rui recalled that distant conversation shortly after his fight with Master Krakule. "You told me that even the grade fifteen Martial Seniors could be divided into fifteen, sixteen, and seventeen."
"Do you recall how many I told you would fall into grade seventeen?" His tone
grew more severe.
Rui's eyes sharpened. "...One."
Master Ceeran turned towards Rui, meeting his eyes.
"He is the one."
Rui considered his words as his eyes swam around. "...And Raijun managed to
get him as his champion?"
"Many people have sought to have the Gatekeeper as a champion, but he straightforwardly refuses them. He has never accepted a request for championship. However, this time...he has changed his mind."
Rui grew severe. "...I see."
"When it comes to the Senior Realm, he is undefeated," Master Vericita informed
him with concern. "Many a Martial Master has challenged him to a duel without
their Martial Minds, just to test their foundations, and he has defeated every
single one of them in the past three centuries. He has lifetimes of experience in war and combat, having been a part of the very first generation of Martial Squires who commenced the Age of Martial Art. He is among the progenitors of the Age of Martial Art with over half a millennium of experience in Martial Art."
"...And what is his Martial Art?" Rui narrowed his eyes. "What is his Martial
Path?"
"His Martial Path is Physicality Evolution," Master Zentra answered Rui's question calmly. "His Martial Art, the Temple of God Style, is a Martial Art that is largely a training-oriented Martial Art."
Rui's eyes lit up. "Interesting..."
Training-oriented Martial Art were those Martial Art a larger majority of the Martial Art techniques were geared towards training the body. These training techniques permanently elevated physical performance parameters to greater heights, increasing the standard output of the body to much greater heights.
"The advantage of such a Martial Art is that there is often no strict upper limit to
the growth a training technique can provide, compared to active techniques and that the gains are perennial and permanent," Headmaster Aronian remarked. "The disadvantages, of course, are that it takes a large amount of time to maximize the potential of each training technique."
He turned to Rui with a hint of angst.
"He has been training for more than five hundred years."