I own nothing but my OC.

Chapter 45: The Tangled Web

"Like I said… Sumiko needs her rest, so what are you all doing eating your breakfast in her room?" Koudou demanded curtly as he, Kazama, Amagiri, and Shiranui all sat around Sumiko while they ate, who was eating off of her tray in her futon.

"Having our medical advice be ignored must run in the family…" Sumiko commented as she sweat-dropped, chagrined. "Why are you here?" She asked the three oni.

"We're sick of eating with all those noisy and sweaty guys." Shiranui replied unapologetically. "It's obvious we'd prefer the room with a flower in it."

"Flower…?" Sumiko asked with a wry smile. "You sound just like Sano-san."

"Sano-san?" Koudou asked curiously.

"Harada Sanosuke. He was the only one who treated me even remotely like a girl." She explained. "Aside from him and Hijikata-san, all the others kept calling me 'Aniki' and so on…"

"Aniki…?" Amagiri said, blinking.

"Yeah." Sumiko said with a sigh and small laugh. "It all started after Heisuke's group saw me save a cat while we were on patrol… I don't get what the big deal was, but apparently they thought the way I did was really 'manly', and they suddenly started asking if they could call me Aniki. I told them no, but they did it anyway…"

"Hah! I can definitely see that happening." Shiranui said with a grin. This woman had enough guts to try to fight and talk back to them, after all.

"Oh, that story reminds me..." Sumiko said as she lowered her chopsticks. "There's something I've been meaning to tell you, Amagiri-san."

"Me?" Amagiri asked, tilting his head slightly to the side while everyone else in the room glanced curiously at him.

"Yeah, so come here." She said, waving him over. Amagiri obediently did as she asked and knelt down beside her futon.

"Closer." Sumiko said, gesturing for him to lean down, as if she wanted to whisper something to him.

WHAM!

"!?" Amagiri said, startled when she suddenly head-butted him with all her might. "Why… Why did you hit me with your head?" Amagiri asked, slightly chagrined, as he rubbed his sore forehead.

"Because it's the hardest part of me." Sumiko deadpanned. "That's for Heisuke. You know, that kid you almost killed at Aburanokoji."

"Oh! The one you brought back to life?" Shiranui asked brightly as he remembered the impressive feat. "That was really shocking! How's he doing?" Sumiko frowned and bowed her as she looked down at the cover of her futon.

"I couldn't stop the bleeding." She said sadly. "In the end, he became a rasetsu."

"Hmph. Indeed, they're all fools." Kazama, who had been silently enjoying his breakfast, said cynically. "That man, Hijikata Toshizo, became one as well." Sumiko's eyes widened in horror as she stared up at him.

"… You're lying." She said, not wanting to believe it. "Why would he—"

"It is true." Amagiri said as he got back on his feet and walked over to join the others at the door so they could leave for their mission. "I witnessed him fighting Kazama in the form of a rasetsu for myself."

"No…" Sumiko said quietly, shaking her head, as tears started to form in her eyes. Not Hijikata-san. Not him, too!

Kazama narrowed his eyes slightly and frowned when he saw the look in her eyes. He didn't like it.

"Let's go." He said, taking his tray with him as he stood up and headed for the door. Amagiri bowed politely before obediently following suit.

"Eh? I'm not done eating yet." Shiranui said, frowning.

"You are now. Come." Kazama said, giving him a sharp look. Shiranui grumbled but he picked up his tray and left with the others. Kazama glanced back to see Koudou pulling Sumiko into a fatherly embrace, trying to comfort her, while being careful of her wounds. He closed his eyes and shut the door, leaving the two of them alone, while she mourned Hijikata's foolish and rash decision to become a rasetsu.

After a moment, Sumiko clenched her fists and blinked back her tears as she lifted her head with a determined expression on her face.

"That settles it then." She said resolutely as she glanced at Koudou. "Sensei, this has been on my mind for a while now… I want to make a cure."

"A cure?" Koudou asked, furrowing his brow.

"For the rasetsus. I want to cure them." She stated determinedly.

"But that's…" Koudou said hesitantly.

"They're suffering, Sensei. It's too pitiful! They think they're not human anymore, but they are, and that's the problem. Their human bodies can't keep up with the demand their new abilities puts on them. Advanced healing… advanced muscle performance… these are all things that would require an extraordinary amount of blood, but their bodies are still only producing the same amount as before, so it puts an immense strain on their bodies to try and reconcile this huge gap between supply and demand. Their bodies simply can't keep up, and it causes them such excruciating pain that they lose their minds, and their body instinctively begins to seek out whatever its lacking in the worst way. Even if they manage to stay sane, the physical strain on their bodies will eventually kill them, won't it, Sensei?" She asked grimly, staring evenly at him.

"You… How did you find out about all of this?" Koudou asked, stunned. "They didn't make you…"

"No." Sumiko replied firmly. "They never even asked. I wanted nothing to do with that terrible medicine, but a couple of the rasetsus had been patients of mine at one point. I just couldn't leave them be, so I kept my eyes and ears open to learn what I could without getting too involved with the Ochimizu itself. Sensei, you left because you came to the same conclusion and wanted them to stop, didn't you? Help me end it, please." She bowed her head low while clutching the futon covers tightly in her fists.

"All right." Koudou agreed after a moment of silence with a small smile. "If you're that adamant about it, I'll do what I can to help you. Knowing you, I'm sure you already have a theory or two?" Sumiko nodded and smiled, relieved.

"Yes. I already tried making a powdered supplement with the same nutrients found in human blood and had Matsumoto-sensei give it to them under his name," She began, "but I've heard it only works for a limited time before its effectiveness wears off, and it's no longer enough to curb their bloodlust. Looking at the list of symptoms they're suffering from, I realized the rasetsu shared a lot of similarities to the vampires of European folklore and werewolves, whose legends are thought to be inspired by Viking berserkers. Both of these creatures are said to share a weakness against silver and are more active at night, like the rasetsu. I think both of these creatures are the result of different strains of the Elixir, but the ones who bear the closest resemblance to our rasetsu are the vampires; a silver allergy, photosensitivity, bloodlust, superhuman strength and healing abilities, only capable of being killed by beheading or a stake through the heart… It all fits. And did you know, Sensei, that there is a certain illness that was once referred to as the 'vampire disease' in that part of the world?" Koudou's eyes widened. "Mind you, the so-called disease isn't actually a transmittable disease and has nothing to do with vampires, but a genetic disorder usually inherited and passed down from generation to the next. It's correct name is porphyria. Porphyrias are a group of genetic disorders caused by problems with how your body makes a substance called heme. Heme is found throughout the body, especially in your blood and bone marrow, where it carries oxygen. There are two main types of porphyrias. One affects the skin and the other affects the nervous system. People with the skin type develop blisters, itching, and swelling of their skin when it is exposed to sunlight. The nervous system type is called acute porphyria. Symptoms include pain in the chest, abdomen, limbs, or back; muscle numbness, tingling, paralysis, or cramping; vomiting; constipation; and personality changes or mental disorders. These symptoms come and go. Sound familiar?"

"Yes, aside from the skin lesions…" Koudou said thoughtfully, nodding.

"I think the reason those haven't manifested is because their skin cells are constantly repairing themselves at such an incredible rate, any blisters heal before they become noticeably visible."

"And what is this 'heme' you mentioned?" He asked curiously.

"Heme contains iron and gives blood its red color. The production of heme takes place in the liver and bone marrow and involves eight different enzymes. A shortage of any of those enzymes can create an excess buildup of certain chemical compounds involved in producing heme. The specific type of porphyria is determined by which enzyme is lacking. Those with porphyria often have trouble processing iron. I think, in the case of the rasetsu, iron is not the problem, but nickel, because it is actually the nickel in silver that causes allergic reactions. Like iron, nickel is everywhere, so there's no escaping it. Because their body is constantly fighting against the small but steady amounts of nickel it is absorbing from the environment, in addition to not being able to make enough blood, they are in constant pain. Taking in more blood helps to solve these two problems: 1) it gives them more blood and helps them heal faster and with less pain, and 2) it helps to dilute the nickel, which is the root of the new kind of porphyria that they all seemed to have developed as a side effect.

"In other words… if we can figure out how to stop the porphyria, then they will loose their sensitivity to light and silver?" Koudou asked with wide eyes, astonished. "I see… that's incredible… so it was the nickel!"

"Yes, but I don't think it will help much with the bloodlust." Sumiko said, frowning. "I think the only way to stop that is to somehow find a way to return their metabolisms to normal again and stop the constant processes of advanced healing and muscle strength. That's why we need to find a way reverse it and turn them back into normal humans. I'm just worried about whether or not it may prove too much of a shock to their system…"

—∞—

"How is she?" Kazama asked when he finally saw Koudou again several hours later.

"She wore herself out again." Koudou replied with a wan smile. Her work ethic and theories were incredible, but he really shouldn't be letting her do something like this just yet. After much debating he had finally convinced her to leave most of the research to him until she was in a better condition to work on it herself.

"Hnh. She wore herself out, you say? She really cried over that man that much?" Kazama asked with a frown. Koudou blinked as he glanced at him.

"Are you jealous?" He asked. Kazama simply huffed and furrowed his brow as he crossed his arms and looked away.

"You don't find it odd for an oni to care so much about a human?" He retorted.

"Well, for her whole life, up until now, Sumiko thought she was one." Koudou said reasonably. "A strange human, but a human nonetheless. It's just how she is. Once she gets attached to someone, she feels responsible for them."

"Hmph. Koudou." Kazama said with a rueful smirk ghosting on his lips, as he closed his eyes. "You have a daughter and a have lived with that woman for two years, but it seems you know even less about women than I." The smirk fell from his lips as he opened his crimson eyes. "The komainu is obviously in love with that man."

—∞—

Kazama was in dark mood as he stalked toward Sumiko's room. He slide the door open with more force than necessary, startling her awake.

"Kazama-san, what…!?" Sumiko began to ask, furrowing her brow, as she pushed herself up into a sitting position, when Kazama reached out and grabbed her tightly by her uninjured shoulder and tilted her chin up so that she was looking him directly in the eye as he spoke.

"I've just had an idea." Kazama said, smirking, as he stared down at her confused expression. "I was going to bring Yukimura Chizuru over to our side, by force if necessary, but… perhaps I can be persuaded to change my mind, if you accept my proposal."

"Proposal?" Sumiko asked, frowning, as her confusion deepened.

"I will stop pursuing Yukimura Chizuru if you will consent to take her place as my bride." He stated seriously. Sumiko's eyes widened in shock.

"What? But I—"

"You are very strong for a half oni." He said firmly. "And any children you have with another oni will be stronger still. The strength of our blood is cumulative when not spread thin and diluted with human blood. What's the matter? Don't you want to save your friend?" He taunted when she hesitated to answer, feeling a little mean-spirited in his jealously.

"Of course… but this is marriage you're talking about." Sumiko said, furrowing her brow. "Till death do us part—that's a big decision! You can't just drop that on me so suddenly and expect an immediate answer. I need time to think it over…"

Kazama narrowed his eyes as he continued to stare down at her stoically. After a tense moment of silence, he finally released her.

"Very well." He said as he stood up and turned to leave. "I'll give you until you've fully recovered to think it over." He couldn't do anything to an injured woman anyway. "… Don't try to run from me, komainu." Kazama said sternly as he paused in front of the open door and glanced back at her. "That's your only warning." He shut the door behind himself, and Sumiko flopped back down onto her futon, wincing slightly from the impact.

"That's not much of choice… What the hell am I supposed to do now?" She wondered aloud as she stared up at the ceiling. Run away? As if she could in her condition! Before she could try anything that risky, she was going to have to bide her time until she was in much better shape. 'I'll worry about that once the deadline's closer.' She decided, hoping Kazama wouldn't try anything until then. 'For now, I'll use the time I'm stuck here to work on that cure...'