Seeing that the story arc is beginning and that he is already in the Human world, Keiko decided to begin his Human world phase, He firstly using the theory of Gigai made by Urahara created one artificial body for himself.
After gaining a physical medium to interact with the human world he decided to play a visit to the nearby hardware store where he used his EMS to manipulate the human in charge of giving a laptop free of charge, after taking the laptop Keiko went into a good 5-star hotel which had a good enough wifi of that time and stayed in a room using EMS free of charge. Keiko with laptop started robbing people online from other countries and such making himself more richer in human terms, the world of SAO was way more advanced than the bleach world thus, Keiko even without using Hope accumulated a large sum, and created himself a fake id along with all the necessary documents and purchased a large house for himself along with many other items.
He used the property as a base started expending his Human world empire and started building a new Hope AI, SAO world virtual world, and world seed for himself. He slowly and gradually without giving a damn about Ichigo and Rukia's adventures started gathering talented people from all over the Human world under himself. He also started teaching his Arrancar regarding technology and various other subjects slowly making them more intellectually capable too.
He also started modifying Gagai Technology to make it suitable to his Arrancar too. Slowly working toward everything creating a base for himself months went by.
One of Arrancar who was responsible for keeping an eye on Rukia reported the Rukia being captured and taken back while Ichigo blade being broken by Byakuya. Seeing that it's time, Keiko left the newly constructed Hope AI which was in physical form in the human world to complete Virtual Reality and World seed while retreating all the Arrancar back into his personal space along with Vasto Lorde.
Keiko traveled back to the Royal Palace and meet with other members informing them that of his speculation of a war happening with the soul society soon. Ichibe and other members didn't care about the wars that Soul society was involved in but due to Keiko being dragged into it earlier paid attention to it.
Soon, the news of the execution of Rukia made it waves through the entire soul society, Keiko took his leave with the excuse of monitoring the situation closely and left for Soul society.
In the soul society, he seats back and watched the situation, Aizen with Center 46 under his control running wild, Captain-commander Yamamoto checking every captain and their activity carefully trying to identify the traitor which Keiko has informed him about while Byakuya struggle between his chose of duty and family with his promise.
Yamamoto with the help of Unohana at the moment suspected Sei Feng, Gin and lastly Toshiro Hitsugaya. Sei Feng due to her connection with the exiled Shinigami Yoruichi Shihoin, Gin due to his suspicious and secretive nature while Hitsugaya due to his friend's death due to Zanpakuto decision made by the center 46. All of them were kept under close observation by Unohana along with the first lieutenant of division 1 under Yamamoto Chōjirō Sasakibe.
Keiko simply watched the situation go on, beginning with the Invasion of Ichigo starting, he was mostly interested in Sado and Orihime's power and much later in Ichigo when he fights Byakuya and turn into human thus decided to stalk Sado fight, he was a fullbringer who according to Aizen was given power by Hogyoku, Keiko followed Sado around and watched him fight, all the data was directly uploaded into Hope via which he could rewatch and analysis the situation more closely. Orihime's potential only came out much later in the story thus he decided to focus on Sado for now. Finally, Sado runs into Shunsui Kyoraku who instantly defeats Sado thus ending Keiko's fun. With this part of the story ending Keiko decided to visit Ichigo and watch his beat all the odd like every Show MC does to save the girl.
Ichigo was fighting against one and only Zaraki Kenpachi, Keiko decided to join Yachiru Kusajishi who was watching the fight from the roof. Yachiru seeing Keiko simply ignored him and continued watching the fight with both people falling down Yachiru jumped near them, Yachiru simply looked at Ichigo and smiling said: Thanks for fighting Kenny.
then she picked up Kenpachi and smilingly said again: It's been a long time since Kenny chan had so much fun. Ichigo if you can don't die okay, and if you can play with Ken-chan once again okay?
Keiko jumped off the building too and slowly lifted Ichigo in the air by the neck like a lamp and watched him more closely, there was nothing too special so to speak about Ichigo or his power, Ichigo had some consciousness and was able to see him and thought that another enemy is here and slowly closed his eyes waiting to either be taken prisoner or killed. Keiko slowly said: Boy it's not time for you to die yet, You still have to dance a little longer and entertain me. Here you can take him cat, I'm simply an observer here. I have worked on his wounds a little rest is up to you and him if he wants to save that little girl.
Keiko throw Ichigo into an upcoming cat shadow and disappeared from there to appear again on top of prison tower where Rukia was kept and Ganju along with Hanataro appeared and opened the gate of her cell to let Rukia out but then started their emotional drama due to Ganju identifying Rukia to be the killer of his elder brother which was interrupted by the arrival of Byakuya who after more emotional crap Ganju tries to fight but is taken out in a single attack, and is saved by Rukia's captain Ukitake and just as they were talking, Ichigo rush in from below making an entrance for himself. With emotional crap being thrown left and right, Ichigo challenges Byakuya to a fight and almost matches him in turn of speed but just as Byakuya is about to release his Shikai, Yoruichi Shihoin arrive sealing his Shikai surprising everyone.
Youichi and Byakuya get ready to fight each other but just as they are about to start Youichi attacked Ichigo but before she could harm him, I huge pressure fall on everyone bringing everyone including Byakuya and Ukitake to their knees. Keiko jumped down from the tower revealing himself to everyone.
Keiko lifted Rukia by the neck with one arm and carefully looked at her trying to understand why the Hogyoku have done anything to fulfill any of her wishes but just shrugged his shoulders and throw her back into prison, Byakuya used all his power to try and stand up but more he tried the more pressure fell on him. Keiko calmly walked past Byakuya and Yoruichi and lifted Ichigo by the neck and said in a cold voice: Boy this is the last time I'm letting you live, 3 days I will give you three days to gain Bankai and defeat Byakuya if you fail I will kill Rukia and all your other companion in front of you. Then throw Ichigo back to Yoruichi and said: Run along little cat I'm here as an observer only or you all would have been death before even knowing about me.
Yoruichi taking this opportunity to run away with everything she had. Keiko simply smiled at the kneeling Ukitake and disappeared along with his pressure.
Keiko with 3 days to do nothing left-back for the human world to check progress regarding everything. Virtual reality project was ready and can be launched into the world everywhere, meanwhile, World seed was slowly being created within the virtual world itself. Calculations regarding the Gagai body for Arrancar being done and the test is started. Due to too much power within each Arrancar, Keiko also decided to build something like Spiritual limiters so to not decompose the Gagai which they are in. Another project for Vesto Lorde and their human artificial body also started with 3 days up. Keiko decided to went back to the soul society just in time for various captains to gather on top of the Sōkyoku ground. Keiko also arrived then and took a chair from his dimension to seat on and watch the show while eating popcorn.
Captain-Commander Yamamoto and others sensed someone seating behind them and looked to find an every smiling Keiko seating there while eating something. Yamamoto knew Keiko's involvement and was ready for any kind of attack but saw Keiko simply waiting for something to give, out the order to start the execution. Keiko smiling watched the Sōkyoku being released from its binding and ready to attack Rukia, Ichigo rushing in front of the Sōkyoku to stop it with only one arm with blade behind his back.
Yamamoto seeing this jumped out gave the order to attack and kill the intruder but before he or anyone could do anything Ukitake and 8th Division Captain Shunsui Kyōraku seal and destroy Sōkyoku surprising everyone, Ichigo while holding Rukia in one hand removed the blade from his back with another and was about to stab the Sōkyoku stand when Keiko appears next to him and stopped his blade. Ichigo surprised put more pressure in it but the blade didn't move at all then he heard the voice of the smiling monster in front of him: Did I permitted you to destroy this little boy?