Yinsen sensed the Reiatsu of Isshin Shiba in his explosive state. It had already reached captain-class levels. It seemed that after Yinsen left the Soul Society, Isshin had continued serving as captain of the Tenth Division.
Picking up speed, Yinsen quickly arrived near the battlefield.
He did not reveal himself immediately. If Yinsen wished to hide now, no one could detect his presence. He had stayed hidden because he had noticed that he was not the only one concealed on this battlefield—there were several old acquaintances as well.
"Aizen..."
Standing high in the sky on reishi, his entire body wrapped in specially made clothing, Sosuke Aizen had not noticed Yinsen's arrival. He was instead completely focused on the battle below.
Isshin Shiba was already injured. Yinsen only needed a casual glance to tell that it was a wound inflicted by a Zanpakuto—it had likely been done by Aizen or Gin Ichimaru. They had stopped after only one slash, clearly intending to suppress Isshin's strength and prevent him from fighting the Hollow at full power.
"Running experiments again!"
The entire early part of the Soul Reaper story was about Aizen, the great villain, madly conducting experiments. Even the protagonist, Ichigo Kurosaki, was merely one of his most prized test subjects—Ichigo Kurosaki's birth stemmed from today's "accident."
After conducting Hollowfication experiments on Shinji Hirako and several other captains decades ago, Sosuke Aizen had spent the intervening years perfecting the technique and creating all kinds of special Hollows. The one currently fighting Isshin Shiba, named White Hollow, was the most special among them.
The original plan had been to throw White Hollow into the Present World and have it attack the Soul Reapers stationed there. But after Isshin Shiba noticed that several Soul Reapers had died under strange circumstances, he came to the