"Hadō Number Four: Byakurai."
Aizen slowly raised his hand. The lightning dancing at his fingertip became a beam that pierced Fujiwara Makoto between the brows, making his body freeze for an instant before he continued roaring.
Several more blasts of Byakurai followed, piercing and destroying his brain, internal organs, and other vital areas. Under Aizen's surprised gaze, the destroyed parts of Fujiwara Makoto's body slowly regenerated.
"So he really is immortal."
Reining in his Spiritual Pressure, Aizen watched Fujiwara Makoto climb off the ground, as lively as ever. A fervent hunger for discovery appeared on his face for the first time in ages. He was an experienced scientist and inventor; otherwise, he could never have created the incomplete Hōgyoku, a veritable cheat in the Soul Society World, entirely on his own. In talent and intelligence, Aizen considered himself no worse than Kisuke Urahara.
His brain had been destroyed, yet he survived.
His heart had been pierced, yet he still would not die.
Just as his memories described, he was a monster that was virtually impossible to kill without a specially made Nichirin Blade or sunlight.
In Aizen's eyes, however, he was merely a peculiar species similar to Hollows. If Aizen truly wanted to kill him, he could devise at least ten thousand viable methods. The gap in their strength spoke for itself.
The simplest method was to erase his soul. A soulless shell was no different from a corpse, and as a Shinigami, Aizen could accomplish that with a mere flick of his finger.
After experimenting on Fujiwara Makoto for several hours, Aizen looked at his tattered body, riddled with damage. Even his demonic regeneration could no longer function, leaving him capable only of helpless roars.
Aizen summarized the characteristics of demons as a species: monsters born from mutations in