[Soul Society...]
Head Captain's room.
Yamamoto had a thousand-yard stare as he stared at Rukia in front of his desk. Rukia swallowed nervously as the head captain watched her with an emotionless face.
"You are to go to the human world and collect information on the outburst of Reiatsu," Yamamoto said as he handed Rukia a purple stone. Rukia nervously took the stone and stuffed it into her.
"Yes! Captain Yamamoto." Rukia saluted as she was allowed to leave the office. Coming outside, Rukia was surprised to see Byakuya Kuchiki waiting for her.
"Brother, why are you here?" Rukia asked as she walked towards Byakuya. Byakuya remained silent, looking at his sister with a bright light in his eyes.
"Careful on your mission," Byakuya said before vanishing from the place with a well-timed Shunpo. Rukia smiled with happiness as she disappeared as well.
[Human world...]
Boom!
Mark grunted as he kicked the air towards Yoruichi, who used Shunpo to vanish. The blade cut into the ground, leaving a gaping hole in the training ground.
"Not bad. I think I like that skill~," Yoruichi said with a teasing smile as she appeared behind Mark in a blur. Mark turned around and barely blocked a kick to his chest.
Boom!
Mark coughed up blood, and his body shattered a mountain in the distance from the force of the kick. Yoruichi jumped into the air, and with a kick, she sent a blade towards Mark.
Boom!
The entire mountain and more were razed to the ground by Yoruichi's Renkyaku. Mark flew out from the rubble with a slash on his chest and blood leaking down his torso.
The wounds on Mark's body started closing and healing at a speed visible to the eyes, and in mere seconds, he was back to tip-top shape. Yoruichi grinned at that.
"Looks like you can handle a little more rough handling~," Yorucihi said as she vanished from the place with shunpo. Mark gritted his teeth as he prepared by using Tekkai on his body.
Clang!
Yoruichi looked in surprise as her kick landed on Mark's chest, making a clanging sound as Mark was pushed back from the force of her kick. But no visible damage was dealt to him.
"You hardened your body with Reiryoku and something else?" Yoruichi asked with surprise as she landed on the ground with a flip. Mark let out a sigh as he felt his chest throb in pain.
"I controlled my blood to flow to my muscles. I then hardened my muscles beyond the limit with a mix of Reiryoku in the bloodstream." Yoruichi and Urahara looked at Mark in surprise.
Quincy uses a similar method to enhance their durability by channelling Reiryoku through their bloodstream. Theoretically, anyone should be capable of this with sufficient Reiryoku control.
"Impressive. I will teach you Shunpo. Listen closely." Yoruichi said as she squatted into a low stance. Her feet were bare, and Mark looked at them with concentration.
Yoruichi's toes curled into the ground like a hand gripping it. Her muscles twitched before she used Reiryoku to push herself off the ground.
No sound was made as Yoruichi vanished from Mark's eyes and senses. Mark only felt a tap on his shoulder as Yoruichi appeared behind him with a smirk.
"Learned it?" Yoruichi asked with a teasing grin. Mark looked down at the ground and got into a low stance. His toes gripped the ground and flexed his foot muscles.
Boom!
The ground under him shattered into a crater as he pushed himself with a pulse of Reiryoku. Mark shot into the distant mountain, destroying it with the impact.
"He learned it in one try? It was sloppy but better than most." Yoruichi said with a satisfied smile. What Mark did is not rule-breaking, but it was better than 99.98% of people.
Climbing out of the rubble, Mark groaned as he tussled the rubble out of his hair. Suddenly, he was kicked in the jaw, sending him into the air like a jet.
Boom!
Rian of punches and kicks fell onto his body before a barrage of punches landed in the same spot on his chest. Mark felt the world blur as a foot landed gently on his chest before it sent him flying to the ground.
Boom!
Mark lay in a massive crater with saliva dripping from the corner of his mouth. His fingers twitched as blood started flowing from his mouth like a river.
Pieces of organs slid from his mouth before Mark's eyes regained focus. His organs healed at a slow rate, and his chest started healing from the purple bruises.
"Seems like your organs will not heal as fast as the rest of your body, but it is not a problem," Yoruichi said as she stared down at Mark. She saw that his body was already mostly healed.
"Fuck... You punch like a truck." Mark said as he stood up from the ground with a sway in his steps. He wiped his mouth from the saliva and blood while looking at Yoruichi like a devil.
Boom!
Mark vanished from his place, and his fist punched past Yoruichi's head, who grinned teasingly before giving a roundhouse kick to Mark's midsection and sending him flying into the distance again.
[Urahara...]
Far from the training ground where Yoruichi and Mark were fighting, Urahara sat in a comfortable chair as Eve and Evie read a manual on Reiryoku and its usage by Quincies.
"You can manipulate matter at an atomic level. Reiryoku should not be any different since it is energy. You only need to know how it works." Urahara explained with a smile as he watched the tablet in his hand.
It showed Mark being rag-dolled as he and Yoruichi continued their fight. He was surprised by Mark's regeneration, but he soon found out that not every Viltrumite could do that.
Anissa is a Viltrumite like Mark, but her adaptation is significantly inferior. It's as if her genes did not even try.
According to Mark, Viltrumites have Smart-Atoms that could evolve to withstand any environment.
As they adapt to gravity, they become stronger and more durable with higher resistance to things.
[Anissa...]
Inside a deep hole with symbols etched on the walls, a heavy gravity acted upon Annisa, pushing her to her limits without breaking her spirit.
The gravity increased every time Anissa stopped leaning from the pressure exerted on her body. Once she was able to stand straight, the gravity automatically increased.
It pushed her Viltrumtie biology to the limit and allowed Anhissa to keep evolving. Her strength has already increased multiple times due to the gravity.
She is becoming stronger.