Time Freeze's seal on Shihōin Naraku could not possibly have been perfect.
Especially when it was meant to restrain a ninja as powerful as he was.
So when Naraku discovered that chakra could shake the seal, he was not surprised at all.
Moreover, while Time Freeze suppressed Naraku, it was also consuming its own energy.
Several months had passed. No matter how powerful this seal was, weak points must have appeared.
Naraku had not tried before because he had been gathering strength all along, without actively probing the seal's limits.
But now, he had to try.
So he began continuously mobilizing the chakra within him.
His chakra rapidly dwindled as he did so.
His chakra reserves, originally at ten percent, had fallen below five percent after those dozen or so assaults.
And under his sustained battering, a clear crack finally appeared in that weak point.
The power of Time Freeze grew chaotic there, and the density of the barrier began to decrease.
Now.
"Thump-!!!!!!"
A deep sound, like an ancient war drum being struck, erupted within Naraku's chest.
It was the beating of his heart.
His heart, which Time Freeze had sealed for several months, resumed beating at that instant.
Once. Just once.
But that single beat seemed to hold immense accumulated power, like a slumbering behemoth suddenly opening its eyes.
The instant he briefly broke through the seal, the chakra within Naraku poured out like floodwaters bursting through a dam. His ten-percent reserve was completely drained in that single strike, with not a trace remaining.
But Naraku no longer cared.
He roared in the depths of his consciousness, pouring all his will into the heart that had just begun beating again.
Heart, start beating!
At that moment, the Drums of Liberation sounded within the Alternate Space for the first