"Prepare the resuscitation bay!" Sakura roared as she burst into the A&E department, wheeling in a trolley bearing a groaning First Hokage. "And someone get the Second Hokage here, I need background on his brother's medical history. NOW!"
The A&E department was a wing that had been added to the Hokage Residence during Tsunade's tenure, and which Sakura had insisted be included in the new building that was rebuilt after Pain's invasion. This way, she could do both her job as Hokage and take care of fringe cases that ordinary medics and doctors couldn't handle, without even having to put a foot outside!
Beeeeep.
"His heart's stopped, stand clear!" Sakura said, jerking her head to signal the medics rushing towards her to stand back. She tore open the First Hokage's kimono and flashed through three hand signs. "Chidori!"
Lightning danced at her fingertips, and she lightly pressed her index against his bare chest, causing him to arch his back in a jerking motion… and then he fell back limply onto the trolley. Naruto's yin-yang miracle act, chest compressions and artificial respiration had already failed back in the banquet hall, so if upping the voltage also failed, then she would have to get creative…
"STOOOP!"
Without warning, the Second Hokage appeared next to his brother, batting away Sakura's hand as she prepared a second discharge.
"No chakra, you'll kill him," he said breathlessly. "Do you have a regular defibrillator?"
Sakura nodded. "In the resuscitation bay."
The medics flung open the doors to the resuscitation bay and Sakura and Tobirama rushed inside, pushing the comatose Hashirama into the room. Without wasting any time, Tobirama charged up the defibrillator to maximum intensity and shocked his brother's chest with the pads, jolting him awake.
"Tobirama," Hashirama choked out, coughing smoke. "I—"
"Save it, you damned fool," Tobirama snapped. "How could you keep your condition a secret from me again, Elder Brother?"
Sakura looked at the Senju brothers in turn. Apparently, they knew what was going on, and if she remembered things correctly…
"Could this be…" Sakura said slowly, "the secret behind the mystery of the First Hokage's death, fifty years ago?"
"Meridian Degeneration Syndrome… I named it myself," Tobirama replied curtly. "It was incurable in our day, and I doubt anyone's come up with a cure since."
Sakura racked her brains, but the term was unfamiliar to her.
"How can you be so sure?" she asked. "Maybe if I look in Lady Tsunade's old notes, it'll come up…"
Tobirama shook his head.
"As far as my research has revealed, only two people in history have ever contracted the disease; naturally, there's been little incentive for doctors to devise a cure for something no one expects to encounter in their lifetime," he explained. "For one thing, you need inordinately vast chakra reserves,and your body must also harbour chakra from an external source to even fall ill."
Well, that was rather worrying, Sakura thought to herself. She and Naruto both had inhuman amounts of chakra, didn't they? And they also possessed chakra that wasn't exactly theirs… Were they also going to die of this mysterious disease, one day? Good thing she had an Ōtsutsuki physique…
"You and your friend ought to be fine… judging by your chakra signatures, you have nowhere near the amount of chakra Elder Brother possesses, and neither does Naruto, since he hosts only half the Nine-Tailed Fox," Tobirama sighed, as if reading Sakura's thoughts. "Lady Mito was the jinchūriki of the whole beast, and she never came down with the disease. She died at the ripe old age of seventy-nine… though, come to think of it, that is rather young for the Uzumaki clan."
"But Naruto isn't a full Uzumaki," Sakura said worriedly. "I'd even go as far as to say that his bloodline is on the thinner side."
Using the Hagoromo clan's Kekkei Genkai, Sakura discreetly sent some of her cells into Hashirama's body to check out the condition of his chakra pathways. Had it been anyone else, she would instantly have been reverse-parasitised by the sheer life energy contained in his cells, but since she already possessed Wood Style, she was fine… though what she found horrified her.
When the Sage of Six Paths first shared chakra with humanity as a means of linking their spiritual energies together, humanity developed the illusory organ known as the chakra pathways, and this genetic pollution, or rather evolution, was transmitted to their descendants.
The further one travelled from the shinobi continent, the more undeveloped people's chakra pathways became; if one went to another continent, one would be hard-pressed to find anyone capable of extracting even the slightest amount of chakra from their cells.
Before long, the cells, tissues and organs of these new humans had become inextricably linked to their chakra pathways, especially so in the case of Ōtsutsuki descendants. That was why the Hyūga clan's Gentle Fist was so damaging: chakra forcibly injected into one's pathways would take the path of least resistance and travel backwards to attack the vital organs from within… the reverse process of extracting chakra from one's cells.
But at the end of the day, despite all the adaptations people had evolved to handle it, chakra was not innate to humanity: having chakra running through one's system was, ultimately, not a natural state for humans to be in.
"His body is rejecting its own chakra, for reasons unclear… early onset of irreversible degradation in the chakra pathways; they'll continue to narrow, until eventually they wither shut, permanently sealing off his ability to use chakra," Sakura murmured. "And in the First Hokage's case especially, damaged pathways mean the excess life energy stored in his mitochondria has nowhere to dissipate, leading to cell membrane rupture… eventual total organ failure."
This was worse than she thought.
Even if Hashirama ceased living as a shinobi and stopped eroding his own pathways with his own formidable chakra, the degeneration would continue. In essence, he was a living, breathing, walking and talking God Tree… and fixing this was beyond the reach of modern medicine or yin-yang style. Whatever atavistic mutation had granted him Wood Style was driving his cells to produce chakra his body had grown allergic to. The barrier between plant and animal was never meant to be breached in species as complex as humans, after all.
"You said two people developed this syndrome throughout history," Sakura pointed out. "Who's the other one?"
"As far as I can tell, judging from historical records…" said Tobirama, "the Sage of Six Paths."
Sakura blanched.
If a half-Ōtsutsuki like the Sage of Six Paths could come down with this disease, then didn't that mean she was also vulnerable? There went her plan of pumping her tits full of infinite amounts of fat to achieve godhood… though she had already abandoned that idea a year ago after discovering that the extra fat was making her chest softer and jiggly in a rather unwieldy way, since fat was less dense than glandular tissue.
"Back then, I ran out of time to save Elder Brother… mostly because he hid his condition from everyone, to avoid showing weakness to the other villages, since it seemed like were heading towards total war," Tobirama sighed. "Perhaps this time, I will have enough time to unearth more leads… the Sage of Six Paths went on to make a full recovery, so he must have found some way to reverse his condition."
Sakura nodded. "I'm making this our number one priority," she said vehemently.
"I know I don't say this often enough, but for an Uchiha, you're all right," Tobirama said, offering her a firm handshake, "You're one of the good ones, like Kagami."
"You really need to work on your compliments, Tobirama," Hashirama sighed. Without warning, he stiffened up, then curled up into a ball. "Ouchie…"