The yellow flash of jujutsu high

Time skip

It's been a few days since then...Keitaro woke up from his bed before looking at his hands, even if it had been so long since the incident had happened he felt so weak.

He was utterly powerless against the face of that man....sure Gojo had easily defeated him later on but if he didnt let his worry get to him to check on Gojo and be his backup, Riko would have been alive.

She would have been fine if he wasn't just so weak....he used to feel so strong but now it all came crashing down to him, the reality was a bitch and it made him realize something very important about this world.

He must never get comfortable, strength doesn't come to those who sit around, he must change his mentality to truly become strong, he must stop feeling contempt for being second place in terms of strength.

He must strive for the absolute best and nothing less, he must essentially become another version of himself.

If Gojo had become the strongest sorcerer alive then he would be the fastest using his technique, he would move faster than Gojo's six eyes could track him, and he would in essence become a yellow flash.

Considering the faster he moves the more damage he will be able to deal with, he would be able to make up for his lack of strength using that.

The best way that he knew to upgrade his technique so far was by using his knowledge about barriers to extend his range so why not just do that?

He will then get a shikigami to have extra storage for his tools or an extra battery, and then a domain expansion.

He must also master all of his chants and make them shorter, optimize all of his techniques, and find a way to absorb the energy from that weird place into his body to become stronger.

He already was thinking of ideas for a binding vow that could help him greatly, his whole stick is about speed so what if he made a binding vow where his most complex techniques would require a hand sign that would be obvious to the opponent and would slow him down but in exchange the technique power will be boosted along with its speed and its efficient.

That was a fair trade-off in his opinion, he needed to study space and time to come up with a more complex way to use his technique.

Being so close to death had made Keitaro more motivated than ever to become stronger and faster, he didnt want to feel himself being out of speed again...he was the fastest for a reason, no one in the school could beat him in speed, and that made him cocky but now all that led through was the death of a girl he considered his little sister.

Keitaro's eyes gleamed with a blue bright color as his determination showed bright, the necklace that his grandma had given him seemed to resonate with his desire to become stronger, Keitaro felt as if his parents along with his grandparents were holding him close to him...

Wait.... no.

As soon as thoughts entered his mind, Keitaro immediately teleported inside his grandma's house and started to look around the house yelling out "Grandma where are you"

Keitaro looked around the house and found nothing that was until he reached the kitchen and saw her, she was lying on the floor looking weak.

"Grandma are you alright" Keitaro said as he rushed by her side and offered her his assistant, "I can see the light"His grandma replied.

"Grandma don't, please stay with me," Keitaro said as he held her close to him.

"My beautiful boy, I truly adore you," She said as she softly touched his cheeks.

Keitaro could feel her energy dropping fast so he used reverse curse energy to keep her alive, he was trying his dam hardest to save her.

"How was school, how are your friends "His grandma said with a gentle smile to which through tears in his eyes he replied.

"It's going fine, I am doing great, classes aren't boring and I get along with everyone."

Tears started to violently leave his eyes as he felt them, the second he ran out of curse energy she would die, she was alive due to him healing all of her organs over and over again keeping them alive and well.

However, it seemed like aging was about to take her from him.

"Don't cry my sweet little boy," She said wiping away his tears but they kept coming back.

"I am trying but it's very hard not to, "He said in tears as she just smiled at him before saying "Everything has to come to an end my little speedster"

"But I had so much more I wanted to see, you can't die on me like this"Keitaro said looking at his grandma he refused to let her go.

"My little sweetheart, don't worry about me, everything good thing must have an ending so don't be sad that I am dying, you will still have all the memories we have together," She said gently.

"But...But.."Keitaro was trying to say as she just smiled at him before saying "You better turn that frown upside down, that my last request as your grandma, to go on, "She said as the light started to vanish from her eyes.

A bead of sweat trickled down Keitaro's temple, carving a silent path through the soot that painted his cheek. Even with the twilight bleeding into night.

Keitaro's fingers danced, weaving through intricate hand signs, each gesture sharp and precise like a whispered promise. Boar, serpent, ram, monkey, tiger – a silent invocation etched into the air, binding his will to the very fabric of reality. With a final flourish, his hands clasped together, forming a steely cage around the burgeoning power within.

Then, the chant. His voice, rough and raw, ripped through the suffocating silence: "From whispers in the shadows, darkness takes form. Let the night devour, let silence reign, in the embrace of the Unseen Storm."

As soon as those words escaped his mouth, a curtain was made, it was a different from a different current however, Keitaro had made a vow that if he couldn't get his grandma to the hospital before she perished then he would.....in his opinion it was a fair one and so it was accepted.

Just like that Keitaro had teleported infront of a hospital and no one seemed to care as if he appeared out of nowhere it was as if they didnt notice it.....

He had to let go.............. She was pronounced dead that day, it was as if she knew the risk he was willing to take to save her life and she decided to die and save him from the trouble...Keitara wanted to not let her go but he didnt want to curse her.

The worst thing he would want right now is to curse his grandma....he would need some time to himself to get his thoughts organized.

A/N I think some people were able to piece together the reason why his grandma suddenly died.