Recovered.

The entire week felt like he was going through Hell of an training, where an ridiculously powerful Barbarian was preparing him for a war against the world.

"Put more power into your jabs." Jiren commanded sternly as he sparred against his grandson in an hand to hand combat, "Your moves are getting clean, but we're not fighting in a movie!"

"I know!" Issei shouted from the intensity of fighting the old man for the last half an hour.

They had been continously sparring one another for the last week and only had a break of one day, where Issei meditated his Ki to expand his spiritual energy and regain the control of his left hand.

Ever since then, Issei believed he had an upperhand in all of his fights against his Grandpa.

Not only had he regained his left hand, but the process had rewarded him with additional stats increase in his physical attributes.

He had leveled up total of eight times after getting knocked Unconscious on his first day. Ever since then, Issei had been practicing his martial arts knowledge and refining his moves by adapting to his Grandpa's fighting style.

He had finally reached an level where he could stand up to Jiren when he was actively using his Touki to fight him. Even if the difference between thier stats was still vast, Issei could at least match him with his fighting technique now.

Issei took an deep breath through his nose as he landed an powerful punch on his Grandpa's solar plexus.

Jiren staggered back from the hit and genuinely had his eyes from the strength behind that punch, 'When was the last time I was punched so hard in a fight?' His muscles tensed up as he got prepared for the real fight.

Seeing his Grandpa get serious, Issei recovered his posture and took an fighting stance to start all over again.

Jiren's red Aura flared over his body, while Issei's white Aura tried to keep up with its intensity.

"Now let's see if you're able to keep up with someone who was inhumanely stronger and faster than you." Jiren grinned in anticipation, "There's no holding back now. I'm fighting to kill, so survive!"

A chill crawled up Issei's spine as he sensed the incoming attack and immediately moved right to dodge the punch aimed at his face. The gust of wind released by that punch was enough to sweep all the leaves and dust in the backyard.

'It's a chain attack.' Issei read the pattern and focused solely on dodging the moves than fighting back, 'Even parrying those punches would hurt a lot.'

Issei clenched his teeth as he crossed his arms and withstood the sudden kick aimed at his chest.

"I see you've brought out your Renewal Taekwondo." Issei smirked at the challenge and changed his stance to match the Martial arts technique, "Guess it's going to be a fight of kicks now."

"Fight more, talk less." Jiren remarked just as he charged ahead and smashed his right leg on top of his Grandson.

Issei reacted fast by moving away and swept Jiren's leg off just as it landed on the ground. Issei knew that Jiren would recover, so he punched his face with his Ki blasting on his left hand to increase his power input.

Jiren saw the incoming attack and raised his right arm as an guard, but the impact was successful in bringing him down to the ground and Issei took the advantage of this opportunity by landing an rolling high kick on his Grandpa's head.

"You dead?" Issei asked with an smug smile as his Grandpa pretended to be unconscious. He knew this much wasn't enough to bring down the Old man.

"I'll give you this one, kiddo." Jiren grumbled as he got up and dusted his clothes, "You've improved a lot in just a week.. And now that I hear myself, I can't believe how insane your growth speed is."

"I had a good teacher." Issei nodded with an fond smile and bowed to his Grandpa.

Jiren smiled and bowed back as an gesture of respect, "I thought I'll be sending you back just by teaching you the basics, but look at you, you've even mastered my renewal Taekwondo."

"Saying that I've mastered it is going too far." Issei waved off with an humble smile, "I believe I can do better."

"Sure, you can." Jiren nodded in agreement, "But, I have taught you all I could. Do you remember what I told you about my old friend?"

"Yeah, you said training with him or something." Issei shrugged as he remembered the conversation, "So you won't be teaching me anymore?" He asked with an raised eyebrow.

"I think my friend would do a better job." Jiren replied, "He already has an student and he wants to test you both against each other. With what I have taught you, I hope you won't face an miserable defeat."

"Way to motivate your grandson." Issei rolled his eyes.

"I'll inform him that you're ready, but before that." Jiren looked serious as he stood straight to face his grandson, "There's one thing left to do."

"Hm?" Issei curiously raised an eyebrow.

"You might not know this, but our veins carry the blood of an Hero and God from the Ancient Era of Gods." Jiren replied, "I don't know anything about that Hero and his origins, but it's a tradition in our family to test the next descendant of that Hero."

"A God?" Issei scoffed funnily. The last thing he could imagine himself was to be godly in any way. Still, he would humour the old man's wishes.

"Whats the test?" Issei asked.

"Oh, it's pretty simple." Jiren answered easily, "It's so simple that even your father had unknowingly attempted this test."

"Huh." Now Issei was curious.

"Follow me." Jiren stated and gestured at Issei to follow him into the house.

He led him to an room where several scrolls, tomes, quills and papers were laying around. Issei realised that it was some kind of an library from ancient times.

While Jiren started searching for something, Issei grabbed one of the scrolls and took a look at it. He read through the contents and comprehended that it was a method on how to deal with curse spells.

Out of curiosity and interest, Issei started going through all the scrolls to obtain as much knowledge as possible. These information were not that special, rare, or unique, but they at least gave him a way to fight back the unknown.

Spells, barriers, talismans, Ki disruption and whatnot. There was a lot of content! And once Issei was done with the scrolls, he moved onto the tomes, which consisted of all the spells and rituals he could perform by using magic and Ki.

Jiren had already found what he was looking for, but seeing how intensely his grandson was focused on browsing through the contents of the library, he didn't wanted to disturb him.

"Good luck performing those spells." Jiren finally interjected when he saw Issei try something stupid, "Those spells are meant for Youkai, us humans don't have affinity to such magic. And even if a rare few humans do possess magic, our spells are more calcution based than intent."

"Like this?" Issei asked with an smug tone as he lit an small flame on the tip of his index.

"H-How..?" Jiren was stupefied. Sure, that wasn't a spell, but it was still something and Issei did it without uttering a word or channeling his powers through a magic circle.

"Guess I possess an affinity with Magic." Issei shrugged in response and looked at the new notification he had received.

[You have unlocked the Passive Skill Mana Manipulation.]

[Your Intelligence has increased by 6 Points!]

[Your Wisdom has increased by 5 Points!]

[Your Luck has increased by 10 Points!]

Issei was astonished as it was the first time he had gained stats in his Luck Attribute, and that too so much at once.

"Yeah, it's real." Jiren remarked as he touched the flame and scowled at his grandson, as if he were an unsolved mystery.

"Don't look at me that way!" Issei whined and raised up his nose, "I'm just good at things I try, a real prodigy."

"Yeah, yeah." Jiren snorted at his grandson's antics, "You can read those stupid tomes later, now come here."

Issei saw the long rectangular box that Jiren had placed on the table before him. Like an curious child, he wanted to know what was inside.

Jiren opened the box and revealed that there was an sheathed Katana inside it. The Japanese style sword had a normal curved shape even if it was a slightly longer than the usual ones.

"It's rusty." Issei noted with an frown, "When was the last time it was taken out of this box?"

"Thirty years ago?" Jiren thoughtfully tilted his head, "Your father was the last person to attempt the test and it was still that rusty back then."

"What even is the test?" Issei asked.

"You have to hold the Katana and unsheath its blade." Jiren answered with an shrug, "Don't worry, even your father was able to do it."

Issei nodded and followed the procedure. He pulled out the blade from its sheath and frowned a little at seeing how rusted the blade actually was.

The next moment, he felt a little tug on his Ki and the table before him was sliced in two parts the moment he channeled his spiritual energy into the sword. The sword glistened with an eerie power as its blade was covered in an black aura.

"The legendary sword Kantusa." Jiren pursed his lips at the result, "Its yours now, congratulations."

"Wait, what?" Issei was stupefied and turned to his Grandpa with an baffled expression, "Just like that?"

"Just like that." Jiren nodded without an shred of doubt, "Unfortunately, I have not trained in the art of the sword to teach you anything about it. You'll have to learn to control that ridiculous sword on your own."

Issei immediately stored the sword back into its sheath, before he damages anything else in the room. He was never good with controlling sharp objects from the start.

"You can stay in the library and read if you want, I'll go contact my friend." Jiren said as he patted Issei's shoulder and left the room.

Issei sighed and decided to check his Status.

[Name: Issei Hyoudo

Level: 17

Age: 17

Race: Human

Title: The Lost Cause

Strength: 50

Endurance: 57

Agility: 53

Intelligence: 58

Wisdom: 63

Luck: 26

Attribute Points: 34

System Points: 7700.]

He had obtained one level, 1000 System Points, and a Minor Healing factor as an reward for completing the Minor Quest from his recovery.

The Minor Healing factor did not only heal his wounds, broken muscles, bones and other injuries faster, but also helped him efficiently recover his Stamina and Ki after an intense training session.

"I wonder who Grandpa's friend is?" Issei thoughtfully muttered to himself before he started browsing through the contents of the Library once again.

~

AN: The Sword is an OC, so you won't find it on Fandom or Wiki of the DxD series. More details will be given in the future chapters.