The Breast Seal Unleashed

Hidden in a hole deep in the ground, Sakura sat in the lotus position and closed her eyes; her brow scrunched up in concentration. A single bead of sweat rolled down her wide forehead— even the slightest misstep could ruin the past month's efforts or, worse still, cause her head to explode.

'This is crazy. We must be crazy,' said Inner Sakura restlessly. 'We should be using the Breast Diet Jutsu Mode to break out of the encirclement and get to safety. We don't even fulfil the requirements any more— least of all now!'

Sakura shut out her nagging inner voice, and with single-minded determination, she focused on the chakra equivalent of threading the needle. Layer by layer, she continued weaving her chakra into the incomplete Yin Seal, but the high volume of dense breast chakra flowing through her chakra pathway system at that very moment was making the precise nature of her work all the more difficult.

Condensing the Yin Seal under normal circumstances was difficult enough, but with this much chakra bloating her meridians? To put things into perspective, the difference in difficulty could be compared to calmly building a house of cards indoors, versus attempting to do so outside, in the middle of a hurricane!

Even so, Sakura's chakra control had always been exceptional.

If the original Sakura could spare enough brainpower to weave her chakra into the complex Yin Seal in the middle of a battle, then so could she! Hidden in the depths of her hole in the ground, Sakura wasn't even fighting, so she had no excuses for failing to reach full capacity under these comparably easier conditions!

Slowly but surely, with the massive volumes of chakra at her disposal, Sakura filled the bottomless hole that was the Yin Seal— until at last, a deep blue diamond faded into existence in the middle of her forehead…

Sakura's eyes flew open. Success! She had finally completed the Yin Seal; four years in advance, compared to the original timeline!

"System," Sakura demanded, "am I still eligible to redeem the Breast Seal Jutsu?"

Sakura looked down at her slowly dwindling chest.

She felt like a little girl trying out her mother's bra, with her baggy clothes loose on her still sizeable chest— from a massive I-cup, she estimated that her breasts had diminished in size to a large E-cup, or maybe a small F-cup. At this rate, she would fall to an A-cup within five minutes, and once she had run out of breast flesh to burn, the Breast Diet Jutsu would stop on its own.

Even though the Host no longer possesses O-cup breasts, the Host still retains the privilege to unlock any System techniques requiring sizes the Host has previously achieved.

The System had set two conditions for her to unlock the Breast Seal, an upgraded version of the Yin Seal that could hold any type of chakra, as well as in greater quantities:

The first: achieve mastery of the basic Yin Seal.

The second: achieve a 106 cm bustline.

"Good," said Sakura fretfully. "Then I'd like to unlock the Breast Seal!"

Verifying… Yin Seal… acceptable mastery. Bustline… checking memory… confirmed.

Ding! Congratulations to the Host for unlocking the Breast Seal!

Complex Fūinjutsu knowledge flowed into Sakura's mind, and for a fleeting moment, she thought her head would explode.

…Warning! The System has detected that the Host's breast volume is falling dangerously low! The Breast Seal's storage capacity is directly proportional to the Host's cup size— and AAA-cups cannot hold ANY chakra!

Everything had gone to plan so far, but to permanently defeat Kakuzu, she would absolutely need access to the Breast Seal in order to perform a certain Jutsu! Otherwise, without the shortcut of having readily available elemental chakra, the level of difficulty to perform it would be too high!

Still, every cloud had its silver lining— the Breast Seal had inherited the Yin Seal's weakness, in that it needed to reach full capacity before it could be released. With its reduced sealing capacity, Sakura would be able to quickly fill at least one of her two Breast Seals with her remaining time…

And so, Sakura began refining the seemingly endless chakra welling up from her breast into fire nature chakra.

E-cup…

D-cup…

C-cup…

With the amount of chakra at her disposal, Sakura managed to quickly fill up the seal on her right breast with fire-attributed chakra, but she was running out of time— she only had about three minutes left to defeat Kakuzu… and use up the sealed chakra. She had no idea what would happen to the chakra sealed within her chest if the seal's capacity kept shrinking, but she wasn't eager to find out…

Sakura stood up and almost fell over, surprised at the ease with which she could move without the two boulders on her chest weighing her down— and the massive amount of chakra flowing through her system also helped.

"Kakuzuuu!" Sakura shouted, as she jumped out of her hole. "Come out and face me, if you think you're hard enough!"

Upon hearing her call, Kakuzu and his four masked beasts flickered into position around her— though not too close. He could see the chakra radiating from her body, rolling off her in waves— now that she had stopped sending it into her various seals, the excess chakra was leaking uncontrollably through her Tenketsu, making her shine like a beacon in the night— her chakra was so dense that it was actually visible to the naked eye.

The result of some self-sacrificial Kinjutsu, Kakuzu surmised.

Engaging her in combat while she was in such a state would be needlessly risky, but such techniques often had time limits— as long as he kept his distance and waited her out, she would doubtlessly tire herself out on her own.

"Shadow Clone Jutsu!"

There was an ear-shattering burst of sound, as thousands of pink-haired girls poofed into existence around him— in a flash, their positions had completely reversed. She was now the one who had him surrounded— and all by herself, no less!

The thousands of Sakuras simultaneously pointed at Kakuzu, before drawing their right thumbs across their necks in one swift motion.

"You just wash your neck and wait," the Sakuras thundered, their voices joining as one. "If you won't come to us, we'll come to you, you bastard!!"