CHAPTER 19:

EUREKA!

Harry was surprised to find that Rossweisse had woken early the next morning, and it took him a moment to find where she was, in the study of the house. She was bent over a piece of paper, scribbling what looked like an equation with runes rather than Greek letters. He knew, though, that it was some sort of working note for a runic circle like those she had mastered in magic.

"Rossweisse?" he asked.

She looked up to him, looking rather dishevelled, but happy. "Harry…Eureka!"

"Eureka? What have you discovered?" Harry asked. "And did you discover it in the bath?"

"Harry, you know I prefer showers, and I had a quick one after it. I still had a fitful night even after we went back to bed, but I have inspiration!"

"…That's good, Rossweisse, but what about?"

"I want to say it to the others over breakfast. But I think this spell could prove key to Rias' victory…"

As they ate breakfast at the table, Rias said, "Okay, Rossweisse. You have my attention. What spell do you think could help us beat Riser?"

"This!" Rossweisse said, holding the piece of paper in the air. "It's still a work in progress, but I should have it finished by the end of this time dilation period. But before I do that, I need to ask, who here, apart from Rias, knows what stoichiometry is?"

"Uhhh, stoy-key-what now?" Issei asked.

"She said stoichiometry, pervert," Koneko said, before returning her gaze to Rossweisse. "It's in chemistry, about how reactions happen. You know, what reagents are needed. And given that we're dealing with fried chickens here, I'm guessing it's combustion stoichiometry."

Rossweisse smiled. "Great answer, Koneko. You enjoy chemistry?"

"No, biology's more my thing, but I watched Mythbusters. They talk about combustion stoichiometry a lot, and I decided to research it more out of interest."

Akeno nodded thoughtfully. "I see. Given that the Phenex's whole thing is their fire, you're looking into that?"

"Yes," Rossweisse said. "Now, magic tends to violate the laws of physics to a degree, but that violation is made up for in an expenditure of energy. Ice magic, for example, is one of the most taxing forms of magic due to being a localised reversal of the Laws of Thermodynamics."

Issei frowned. "Actually, I know this one from physics class. The Laws of Thermodynamics say that heat must flow to cold, and that disorder, entropy, always increases overall. Even if you're tidying a room, your effort to do so basically turns the fuel in your body into heat that is basically disorder." He noticed the other ORC members staring at him. "What? I actually pay attention in classes, believe it or not!"

"…Let's move on," Rossweisse said. "Now, in combustion, you need one of three things. Firstly, you need oxygen for the flame. You need a heat source like an initial spark from a flint. And you need fuel. I'm not versed enough on magical theory to know how such a thing actually heals a Phenex, unless it's somehow burning away injuries as a concept, but I have an idea that even the magical flame of a Phenex still acts like mundane fire to a certain extent. It could potentially burn in a vacuum because it is magic, but it would consume more magical power in the process."

"I think I see what you're getting at," Rias said, her expression showing a tentative hope. "You are suggesting a spell that creates a localised total or near-vacuum around Riser or Ravel. They could, if they keep their head together, fight their way out of it."

"True, but if they are weightless, and unable to leave the vacuum field, they would be unable to leave until the spell is dropped," Rossweisse said.

"So, what, Riser would pop like a salsa-filled balloon from explosive decompression?" Issei asked, grimacing in disgust. "The guy's a douche, but I don't think I want to kill him, and we're not allowed to kill him in a Rating Game."

"That's a myth," Rossweisse said. "That sort of literal explosive decompression needs a greater pressure differential. You ever watch the James Bond film License to Kill?" The others nodded. "Remember what happened to Krest in the decompression chamber? Something like that has actually happened in real life, to industrial divers working on the Byford Dolphin oil rig in 1983. That would be near-instantaneous death. If you went into space without a spacesuit, though…well, you'd probably swell up a bit, and bleed from a lot of your orifices, but for the most part, it's a lot less grotesque than Hollywood would normally have you believe. You could even survive it if you got back into a proper atmosphere quickly enough, assuming the oxygen wasn't leached from your lungs by the pressure difference."

"…Oh my, you are rather morbid, Rossweisse," Akeno said, with a weak chortle.

"I'm considering angles for Rias to win this game," Rossweisse said tersely. "It's a brutal method, but it should work. Riser should, in theory, be stuck in the vacuum field, unable to leave, suffering from anoxia. Hopefully, it will overwhelm his healing enough for him to be automatically withdrawn from the battlefield. I do need to ask, though…how many dead people have you seen? Any of you? And I don't mean Stray Devils or people revived to join this Peerage."

"…I have to admit, if we are talking about such things, Kiba would win hands-down," Rias said, the Italian boy nodding. "Koneko witnessed the aftermath of her sister's rampage, and Akeno witnessed her mother being murdered by their own family, but Kiba…"

"What went on in the Holy Swords Project…butchery doesn't even begin to describe it," the blonde boy said solemnly. "I saw so many of my friends murdered. Have you ever seen people being gassed en masse, Rossweisse?"

"I count myself fortunate that I have only seen such things in fiction, Kiba, and I'm sorry you had to witness death on such a scale."

"And yet, you have yourself?" Asia asked.

Rossweisse nodded solemnly. "My first time was at a train crash near Oslo. We were brought in for disaster relief as it involved many Norwegian magicals, and our trainee squad happened to be nearby, so we posed as volunteers at the request of the Ministry of Magic for Norway. It was…horrifying. They make death so neat and tidy in films and television, most of the time. But that train crash destroyed a lot of my illusions. Not long after that, I saw even worse when I met Harry, even if it was to the deserving. And as a Valkyrie, I am required to work with the dead on many occasions. Bringing Einherjars to Asgard may only be part of our duties, but it is still an important one. And we are also soldiers of Asgard, their special forces. We may not see battle as often as many human militaries do these days, but we are expected to be used to death and war. Some of my peers still treat death as a trivial matter, especially as Valkyries, being semi-divine, are near immortal, and can bring back the dead to some degree. But…I do not. Einherjars, Evil Pieces, they are exceptions, not the rule. And Viking culture is steeped in death and violence, as I'm sure you well know."

"Akeno's jokes aside, though, you do not seem morbid, Rossweisse, despite your work as a Valkyrie," Rias observed.

"I do not think of myself as much. Death and war repulse me. I became a Valkyrie not to fight, but to defend," Rossweisse said. "That being said, I will kill if need be, and I have, even if those were Stray Devils and other monsters who prey on the defenceless. But I do not allow myself to be steeped in death. My parents and my grandmother have been a great help in helping me deal with such matters, as has Harry."

Harry placed a hand on her own as a gesture of support. She had talked about such things at times, but it was one of the few times she had discussed it away from her family, or with him. Maybe it spoke to her becoming more open.

"…So, uhhh, getting off the uncomfortable topic," Issei said, "your spell will basically subject that fried chicken douche to explosive decompression, right? And it should weaken his healing power?"

"It'll be tied up healing himself from vacuum exposure, and because there is no oxygen, it'll rely on his own innate mana to burn. Given what I've read about the Phenex flames, it's actually a good hypothesis," Rossweisse said. "There's one caveat, though. The spell is not self-sustaining but requires a continual casting. As Rias and Akeno are the best magic users here, I will teach the spell to them once I have perfected it. I'd teach it to Asia, but she lacks the ability to harm others."

"…Sorry," Asia said morosely.

"Don't be. A healer has a place on the battlefield, Asia, and we are teaching you how to defend yourself without harming your opponents, at least too much," Rossweisse said. "Now, if I'm lucky, I might be able to test it this afternoon…"

"…It's a glass of water," Issei said flatly, as Harry put a glass of water on a stump outside the house.

"It's a good illustration," Rossweisse said.

"Yeah, I think I heard something about this," Harry said. "When air pressure goes down, the boiling temperature of a liquid goes down too, right?"

Rias nodded. "I think I've heard of an astronaut who survived explosive decompression. Before losing consciousness, he actually felt his saliva boiling on his tongue."

"Exactly," Rossweisse said. "In a near-perfect vacuum, water pretty much boils at room temperature. Now, stand well back. I've adjusted the field so it is smaller, but I don't want any of you to get caught in it anyway." Rias, her Peerage, Sindri (who had come to watch the new spell in action) and Harry stood well back, before a runic circle flared into life over Rossweisse's hand. Then, it vanished, only to reappear over the glass and the stump it was on.

The results were fairly dramatic. Bubbles instantly began appearing in the water, as if it was boiling, or carbonated. The glass itself began to float slightly above the stump. Asia and Issei's eyes widened in shock. "Holy shit!" the pervert yelped.

Rias and Akeno applauded, as did Kiba, Koneko, and Sindri. Harry smiled. "Well done, Rossweisse! That was excellent!"

"No, it's not," the Valkyrie said grimly, releasing the spell, with the water stopping boiling. "It's a good first draft, but the efficiency of the spell leaves a lot to be desired. It was chewing up mana like a Hummer guzzles fuel. I can fix that, but it'll take time. Hopefully, the time we have will be enough, especially if I am to teach you."

"Don't sell yourself short, Rossweisse," Rias said. "You managed to create a new spell more or less from scratch and was ready to test it within a day. Even if it needs improving, the fact that it works that well is enough to call your efforts excellent."

"Exactly," Harry said. "As a first draft is concerned, it's excellent. If the mana efficiency is the only problem, I'm sure you'll figure it out. I believe in you, Rossweisse. Just don't overdo it trying to perfect this spell."

She shot him a grateful smile. "Mange takk," she said in Norse, before returning her gaze to Rias and her Peerage. "There are three problems with this spell's efficiency. Creating a vacuum, sustaining a vacuum, and sustaining a zero-gravity field. And keep in mind, this is the spell with the power turned down. You'd need to have a larger area under a vacuum to work against Riser. Between the mana drain and having to ensure nobody attacks you, it's a spell that will need to be used when most of his Peerage is either incapacitated, or otherwise occupied. Given his usual tactics in a Rating Game, that may not be a problem. But this will be your trump card. It will not be what you solely rely on for victory."

"Of course. I wasn't expecting something like this to give me victory, welcome though it is," Rias said. "Honestly, we need to get better, to be better. While I haven't exactly sat on my laurels, I admittedly thought I had more time to recruit and train my Peerage before Riser demanded I be wed to him. And that has come back to bite me."

"Well, you're committed now," Rossweisse said. "I remember something Atreus' father used to say to him. Don't be sorry. Be better. And you're committing yourself to becoming better. That being said, one thing I will have to do with your Peerage is discuss their…issues." She looked at Akeno and Koneko in particular. It wasn't a harsh look, just a gentle and understanding one, but Harry noted that both of them looked away.

Still, he hoped they could help Rias and her Peerage. He'd grown to like them. He just hoped Rossweisse wouldn't overdo it…

"You okay?" Harry asked, as he and Rossweisse lay on their backs, side by side in bed that night.

"More or less…I'm just trying to stop thinking about that spell," the Valkyrie admitted, looking at the ceiling. "It's harder not to think of something that you're fixated on. I know what's wrong with my spell, and I have ideas on how to fix it, but I don't want to burn myself out trying. And yet, Rias' freedom, along with that of her Peerage, is at stake."

"Hey, take it steady, and you'll figure it out," Harry said. "Do you want a distraction from that?"

"If I can."

Harry rolled over to look at her. "Then look at me. Roll over and face me."

She did so, and he gently leaned forward and kissed her on the lips. Just a brief kiss, but something seemed to clear in her eyes. She leaned forward, and kissed him, only her lips lingered. Hands began roaming as they made out in the bed, before Rossweisse eventually broke it off, blushing heavily, but she was smiling.

"Did that help?" Harry asked.

"A little."

"Then I'm glad. Rossweisse, you are smarter than me, and without my Sacred Gear, I'm still behind you in terms of strength and ability. But I am here for you. I am here to help you in whatever way I can, even if that's just being your cheerleader for now."

"You're helping them train, especially Asia," Rossweisse said. "And I'll need your help when dealing with the worst issues of the Peerage members."

"I'm not a shrink, Rossweisse."

"Neither am I, but we both have something important. We have empathy, an ability to see things from other's viewpoints, to understand their feelings. And you have more perspective on what it is like to be treated like trash than I do. You can help me with that."

"Sure. I'll do what I can, Rossweisse."

And so, the two eventually managed to get to sleep, a more restful one than the night before. But they also knew they were up against the clock. And at stake was the liberty of Rias and her Peerage. Time would tell if they succeeded…

CHAPTER 19 ANNOTATIONS:

So, yeah. A bit of physics, a bit of magic, a bit of angst, and a bit of lust.

This solution to beating Riser was actually one I had considered for a possible new Harry/Rias fic I have been working on. However, I thought it was more in-character for Rossweisse, who is something of a genius, to consider this. A lot of ensuing discussion about Hollywood-style explosive decompression and the difference between it happening in space and it happening through a diving bell or decompression chamber is a little bit of education. Yes, the Byford Dolphin accident in 1983 actually happened, and one of the poor divers involved actually did explode. The others didn't, AFAIK, but their arteries were clogged with fat that had come out of solution, due to their blood boiling and denaturing (that is, terminally damaging) the lipoproteins in their blood. So what happened to Krest in the 'Launder It' scene in License to Kill is surprisingly realistic compared to, say, space-related explosive decompression scenes in Outland or Total Recall.

Rossweisse discussing the deaths she has seen was meant to be a natural follow on to that. Rossweisse is not a morbid person, but the Valkyries are, in DxD-canon, soldiers. Rossweisse has already seen death and destruction. Not that Rias' Peerage haven't, especially Kiba, but still…

That little coda of a scene at the end was meant to further Harry and Rossweisse's relationship. Harry may be on the sidelines for now, relatively speaking, but he's very much Rossweisse's support, someone she needs pretty badly. So he's still holding a vital position in the story.

Review-answering time! Beleriond: Yeah, well, my current attempts at a Harry/Rias story are going nowhere for now, so you'll have to wait. Sorry.

jgkitarel: That too, but combat medics can be expected to fight. It's just that Asia has too gentle a demeanour, so they basically work around that.

No numbered annotations this time.