Time flew by, and a year and a half passed in the blink of an eye.
Ever since the battle that had erupted in the Human World ended, both Hueco Mundo and Soul Society had completely cut off contact with the Human World.
Forget clashes between the two sides—they had not even met again.
The whole world seemed to have suddenly fallen quiet, with everyone busy preparing for the coming decisive battle.
Aizen in particular began using every possible method to accelerate the Hogyoku's fusion.
To that end, he did not hesitate to massacre countless Hollows in Hueco Mundo, using thousands of Gillian-class Menos Grande as fuel and catalysts.
As for Allen himself, aside from secretly lending a little help during the Bount invasion of Soul Society and studying their souls and dolls along the way,
he spent the rest of his time in Las Noches, working with the deranged researcher Szayelaporro Granz on the development and application of Reiatsu technology.
Although Allen had no fondness whatsoever for this madman, he had to admit that Szayelaporro Granz possessed exceptional talent for research and development.
In just a few short months, Szayelaporro Granz had helped him complete a series of cutting-edge technological explorations.
Now, even if Allen's soul returned to his body, he could use both Soul Reaper and Hollow abilities without any hindrance.
Not only that!
By constructing a Reiatsu furnace within his body, he had maximized the conversion efficiency of his soul energy and formed a protective barrier made of Reishi over the surface of his skin.
This was a defensive technique modeled after the Quincy's Blut Vene, the Hollow's Pesquisa, and the Soul Reaper's Reiatsu barrier.
At Allen's current Reiatsu level, he could practically ignore the attacks of every Espada ranked fifth or lower after their Resurrección: Segunda