Ren stared blankly at his arms, the sight of them sending him back to that fateful day.
'If only... if only I'd been there sooner.'
Ren stood in there in silence, his feelings a jumbled mess. He felt pride for deafeting the spectre alone, relief that his arduous training did not go to waste, even happiness that he attuned, though those emotions didn't last long.
They were quickly overcome by the sorrow, sadness, and anguish that losing his family caused him.
The most prominent emotion that plagued him however, was regret.
Ren regretted not being there with his family, he regretted not getting there sooner, he regretted telling his sister to stay in that alleyway.
His victory only made him regret not being there even more.
As Ren spiraled down that tunnel of dark thoughts, his core shook. A sudden pain in his chest made his knees buckle.
He knelt on one knee as he coughed violently. A few moments later the pain lessened and he felt the pressure in his chest die down.
"Oh... right, control."
Now that Ren had a core, the Ether in his body was no longer passive, nor was it entirely his.
Ether was the energy of the world, contained in everything, and everyone.
Each element of Ether represented its own effect, color, and emotion. Which is why different types of Ether are concentrated in different environments and areas.
Spirits usually embodied the effect of one element, some exceptions embodying a mix of more than one.
Meanwhile humans, having all kinds of emotions, usually have all kinds of Ether passive within them.
So, when a human feels an intense emotion, the Ether corresponding to that emotion becomes more active in their body. For normal humans, that doesn't have much of an effect other than being more prone to wild attunement.
For strikers however, their core, the center of their Ether, and therefore their being is most affected by their emotions.
So, if a striker lost control of their emotions while not having sufficient control of their Ether core, their Ether flows by itself, consuming their body and returning the spirit they attuned with to "life", if spirits could even be called that word.
That is the biggest danger in the early stages, and also the reason the waiting rooms exist.
Ren took a deep breath and sat down.
He tried to remember the feeling of controlling his Ether.
...
Nothing happened for a while, then Ren remembered that what he previously did was draw his passive Ether into his core. Now, he was trying to do the opposite using the same method.
Realizing his mistake, Ren now shifted his focus on to his core, he could feel the orb of pure energy in his chest, he tried to approach that energy and slowly pull it out of its dormant state.
After a few tries, he felt the energy slowly move out of his core.
Just as Ren sighed in relief he felt the energy retract almost immediately.
'So I have to be fully focused on controlling it, huh?'
He whispered to himself:
"... Maybe that's for the better."
Ren then poured all his concentration into moving his Ether.
After a few tries, he could manipulate it slowly into his right arm. As he did so, he felt movement in it, crawling, itchy movement.
He opened his eyes while carefully keeping his thoughts focused on controlling his Ether. He then looked at his arm and saw a previously clotting wound completely clotted, presumably healing under there.
'Two... No, three birds with one stone, I guess?'
First of all, Ren was training to control his Ether core. Secondly, he was also energizing his cells, vitalizing them, making them heal his injuries faster, and better. If he could keep his Ether there long enough, that is.
So Ren kept focusing his Ether on his arm for what he felt like was an hour, maybe two.
Then, he slowly started trying to extend more ether from his core, towards his left arm this time. Another tendril of radiant, white Ether crawled across Ren's chest and toward his left arm.
At first, it was moving relatively smoothly, no matter how slow. But then, the controlling got gradually more difficult as he got closer to his arm. Suddenly, when the Ether reached his elbow, it retracted from both arms and returned to the core.
"Phew..."
Ren let out a heavy breath as he closed his eyes and tried again, extending a tendril towards his right arm, then another one to his left. After another failure, he tried doing it in reverse.
Failing another time, he was neither discouraged, mad, or disappointed. He was actually glad that it wasn't easy.
After all, the third, and final reason he was so focused on training...
"At least it's keeping me busy."