Orihime fell to the ground with a thud. She landed somewhere outside of Karakura town in a forest. Her arm was still bleeding, dying the grass green. She coughed up some blood from her internal injuries and tried to heal herself. However, her wound and body were overflowing with Yhwach's chaotic Reiatsu. In order to reverse the damage, she had to also reverse the large amount of Reiatsu that had filled her body. The difference in strength was unbelievable.
Yhwach was already so powerful, she could only imagine how strong he would be on the day he invaded. It was no wonder he was able to fight against Ichibe, the supposed strongest Royal Guard, without breaking a sweat. She mused that only Kenpachi at full strength, Ichigo at full plot-armor, and Aizen just being Aizen could face him. The Soul Society was destined to get slaughtered.
Since she was focusing all of her Reiatsu on purging the foreign Reiatsu, she wasn't able to release her bankai again. Similarly, she could not open another portal. She was able to stop her arm from bleeding by tying her sleeve over it, but she was weak from the loss already. There was nothing she could do about her internal injuries except for slowly healing them.
Orihime had wondered why, in the original timeline, she couldn't heal Ichigo from his wounds. But now, having experienced it herself, she can understand. This was a thousand years of anger infused into one of the strongest being's body. Normally Reiatsu outside of the body would dissipate over time naturally, but Yhwach was able to incorporate his will into it. Although she was suffering, this was a new avenue of training she had never realized. However, only a monster like Yhwach could have a will powerful enough to influence his Reiatsu.
Will was something that could only be honed with time and battles. Orihime was confident in her development from battles, but time wasn't something she could control. Although the cleaner was still not replaced, she couldn't simply sit in there for a thousand years. Only the long-lived monsters could have enough experience to form will.
"Dammit, I'm dumb. It's so obvious."
Orihime slammed herself on the forehead when she realized it. She didn't need a long life or a lot of battle experience herself, she could just commandeer it from others. With her vast Reiatsu pool, she could pull half of it outside of her body and use the egos in her bankai form to create clones of those she had absorbed. In fact, every aspect of a Soul Reaper could be replicated with Reiatsu and spirit particles, which she had beyond perfect control over.
However, Orihime seemed to understand something. Once the idea of infusing a will into her Reiatsu came up, she understood what came after one-hundred percent control over Reiatsu. Once you reached complete control, the next step was to fuse your will with it. This explains why Yamamoto's Reiatsu is in the form of flames. He must have completed, or is close to completing the fusion. His will takes the form of his Zanpakuto's flames since they are one in the same anyway.
Several hours passed and at some point, she passed out from exhaustion and blood loss. Eventually, she woke up and found herself in a familiar room. Orihime's arm was properly bandaged and her internal injuries seemed to have healed naturally thanks to her extreme-regeneration. The door slid open and she saw the iconic wooden clogs and green kimono. When she turned her head up, Orihime saw Urahara covering his face with a folding fan.
"It seems you have had quite the adventure, Miss Inoue. Imagine my surprise when Ururu came back in the middle of the night with you over her shoulder. You lost a lot of blood, but healed remarkably quickly."
Orihime checked herself with her perception and didn't see anything strange. She noticed Urahara's questioning gaze and already formulated a lie long before. She turned her head to face the ceiling again and sighed. There was even a slight tear drop that formed at the corner of her eye and fall down the edge of her face.
"It seems I failed their test. I was lucky to not be killed outright and escaped through a portal. I don't know why they let me go."
"I see."
"Where is Yoruichi? I haven't seen her in a while…"
"She's busy beating up Ichigo."
"What? Why is she beating him up? Did he grab her tail?"
"Not quite. His attitude has changed and his friends asked for our help to correct it."
Orihime could tell he was only answering her questions and not elaborating anymore than he found necessary. This was obviously his way of creating distance. Perhaps Orihime was the same in his eyes. Someone that developed a strange personality after becoming stronger. However, Orihime couldn't sit around playing house with these friends and expected this to an extent. Once Yhwach was stopped, there would be plenty of opportunity to mend bridges.
Once her Reiatsu was stable, she would sneak out and start her new training. The best place to go would be Hueco Mundo so that she doesn't harm the environment and alert the Soul Society. Fortunately, she was heavily wounded and severely weakened from her fights that she wasn't a huge beacon when she arrived. It seems that she was quite lucky to have Ururu find her in the forest. That night, she sensed no one was around and changed into her indestructible uniform.
The arm that was cut off only had a small hole in the sleeve from the attack. The durability of the clothing was certainly astounding. Since her bones weren't infused with Oken like the other Royal Guards, she was actually less durable than the clothing. However, they didn't provide much protection, just insane durability. With a bit of spirit particles, the hole was easily mended.
Orihime found her way to an abandoned block and opened a Garganta. Her eyes sparkled in excitement. She had finally found another way to increase her strength, and it would not be a minor change. If she can support two or even three clones, it would be far stronger than a simple one plus one. Even though she has to invest a large amount of Reiatsu, the techniques and economy of action would favor her side. She would also have perfect synergy since they are part of her.
When she arrived in Hueco Mundo, the first thing she did was to heal her arm. Fortunately, the long rest she had was enough to purge all of Yhwach's Reiatsu. The healing of her arm did not take long and she was quickly in tip-top shape. The Arrancar group had since arrived to greet her and figure out the next course of action. During this time, there had not been any invasion which she was thankful for. Orihime told them all to return to what they were doing since she needed to focus on training.
She went through the egos and chose the weakest one, which was the female Quincy. After activating her bankai, she focused on the strength of the girl from her memories and attracted spirit particles from around to start forming the body. She attempted to fuse the girl's ego with her Reiatsu, but failed several times. She was only transforming back and forth and unable to actually package the will and attach it to Reiatsu. After a dozen times, she sighed and gave up.
Instead of getting ahead of herself, she first tried to combine what little power of will she could with her Reiatsu. The hogyoku was useless in her attempts, since this seemed to be knowledge from a higher tier than she had access to. Her attempts lead her down the road of Kido. Whenever she tried to mix an intangible unknown force that was really just a concept like willpower with Reiatsu which she could feel and see, the only reaction she would get is Kido.
"Is this the trick? The reason Kido is taught the way it is, and why there is no teachings about the stages after complete control? Once Kido is mastered, control is mastered, and will is developed over time, perhaps, the final step becomes natural."
While pondering this, she was suddenly alerted to something deep within her soul. The power of hogyoku was very close to awakening. The process had, at some point, slowed down to a crawl. Orihime had stopped monitoring it because it was driving her crazy. The same that a watched pot doesn't boil came to mind. Therefore, she put it out of her mind. However, she was just thinking about the hogyoku and it started to become lively. It was only one step away from awakening. Apparently, the rampaging energies of Yhwach had stimulated it after so long of being inactive. A flourishing feeling spread throughout her body.
Orihime felt as if she were a flower bud that had been closed for a hundred years finally opening and taking in the beautiful air and sunlight.
We're getting eerily close to the end. I don't know how many more chapters there will be, but I hope you enjoy them.