"Wasn't I the one supposed to struggle...?" asked Rina.
"... The presence of mana veins in your body makes it hard for me to force the mana through your skin. I expected that much, of course. But you have no idea how much harder that neutralization property makes this process be. I have to constantly infuse the neutral mana with my signature to regain control before I lose it an instant later," Iris sighed. "I'm confident it's impossible to start your mana system with the usual method."

As she saw the disappointment in the beast girl's left eye, Iris tried to imagine an alternative.

(If manually forcing my way past her skin is too hard, maybe I could use a spell? I suppose all magic types that affect one's brain can bypass those natural defenses. Father's Illusion magic is one of them. Automation has to be the key.)

"Let's go with plan B, but that same property might very well make it fail too."

(After all, spells are thought to need the signature of the caster. Now, maybe it just appears so because neutral mana is by construction not neutral anymore once it has been cast, and spells don't actually need a persistent signature...)

Iris focused on an area next to Rina and then slowly pointed her index finger toward the sky. Right after she did, the beast girl could finally move her arm freely. Following Iris' gaze, she looked up.

"Close your eyes," Iris said firmly.

Immediately after Rina did so, she could make out a bright flash behind her eyelids. "W-what...?"
"So it actually survived the perpetual neutralization...?" Iris murmured to herself, somehow almost as surprised. "I suppose the theory of mana needs a revision..."

What Iris had done was fairly simple. She had taken hold of her neutralized mana long enough to cast a simple spell, and she lost control over it a moment later after it got neutralized once again. Yet, just as she had ordained it to do beforehand, the mana smoothly moved up before it turned into light. 

"Well, plan B might just work out."

***

"I'll now introduce my mana into your mana veins to trigger a defense mechanism that will make your mana circulation truly start," Iris warned the beastfolk. "There must already be a weak flow of mana within your inactive veins, so I'll have to make myself detected by overflowing those veins. Ready?"
"R-ready."

(Up you go!)

"Ngh...!"
"Oh... Sorry. I may have overloaded your veins a bit too much. Are you alright?"
"Yes... The pain lasted only a second."
"That is good to hear. I think we're done, then. See? It wasn't that big of a deal," Iris said as she gently tapped the beast girl's shoulder.
"Ah... Yes, indeed..."

Iris proceeded to teach Rina everything about mana control. Although Rina was part of a different species, it seemed most breathing techniques were still effective.
After not even ten minutes had passed, Rina was already able to tell where in her body her mana was concentrated and to make it move from one arm to another through her veins.

"You're a fast learner. It's a shame no mage ever took the time to teach you this. Being able to cast your magic on demand would have been useful in this career."

(Then again, I doubt she would have found a mage who just happened to have a spell that enters people's bodies with a strong enough output.)

"I'm still an E-rank adventurer, so it will prove useful in the future," Rina smiled at Iris. "Are you truly not charging me...?"
"I'm just happy to help. Plus, if you ask me, it's a much more interesting thing to do than monitoring bandits. Anyway, how about we truly make light of your magic type?"
"Yes!"
"Alright. Then close your eyes, circulate your mana throughout your body, and focus on what you see. It might be black for now, but try harder."
"..."
"What do you see?"
"I can't tell... Lines, maybe?"

Iris nodded repeatedly to herself.

(I guess she has Line magic then... As if! Why are magic instructors still using this unrelatable technique?! That's no better than seeing shapes in clouds or doing a Rorschach test!)

During her magic lessons, Iris had heard that most of the time, the relation between what a mage saw and their element was understood after learning what the magic type consisted of, making it largely useless.

"... Just forget what you saw. We'll try to eliminate one by one all the hypotheses."
"O-okay!"

***

"Thank God, they're coming back," Cyne said while pointing to several carriages coming in their direction. He looked at the bandit he was currently sitting on. "I'll let go of you. Try to run off again and I'll break a limb."
"Right on time..." said Patry as he was pointing to another bandit's face with his sword.

To tie up the bandits, they had made use of the ropes that had bound the party of E-ranks adventurers. However, there had been too many bandits to restrain them all. Although the majority had a few broken bones that prevented them from escaping, a few untied bandits had tried to retaliate at some point.  

"Do you need help?" asked Iris who was followed by a seemingly exhausted beast girl. They had finished what they had been doing for the last hour.
"You're asking that now? Are you two done playing around?" Cyne chastised her with an annoyed face.
"W-well, we weren't messing around at all. I was teaching Rina magic."
"... Magic? To a beastfolk?" Patry pondered.
"Surprisingly, yes. Her element happens to be well-suited to her low mana pool."
"Is this element the one that protected you back then?" Cyne asked Rina directly.
"Mmh... Apparently."
"Good catch," Iris started. "She is indeed the perfect shield. But that's not all. Under certain conditions, she might also be a sword."
"... A sword?" Cyne pondered. Even the beast girl seemed surprised to hear that.
"Well, I'm not sure yet, so I can't give any details. I would have done more tests, but Rina is low on mana right now. I'll experiment more once she recovers."

***

“They’re all alive… Disabling them all without killing anyone is an impressive feat for D-rank adventurers, especially when you are so outnumbered. You’re good!” a guard exclaimed as he was appraising the bandits' state.

The praise would have felt even better for Cyne and Iris if the guard had not been looking at the three members of the Sword Believers who had taken off by carriage. 

(They... didn’t take all the credit, right?)

The three of them noticed the piercing gazes from their leader Patry. "A-as I said earlier, Sir, these three adventurers almost fought by themselves against these guys... The beast girl helped a lot too, I heard."
“Then, you four are quite skilled... Well, you should still get the same reward anyway. Just split it as you see fit."

With brisk efficiency, the guards bundled up the captive bandits and loaded them into their wagons. As for the adventurers, only the Sword Believers came back with the baroness’ second carriage they had used earlier. The E-rank party to which Rina belonged was nowhere to be seen. When all the carriages started their trip towards the city, Iris decided to ask.

“Rina... Is your party dumping you or something?”
“Huh... Looks like it?”
“Oh... I'm sorry for you.”
"I don't really mind. I would have left myself if they did not dump me.”

(I suppose she doesn't want to go on missions with people who she knows would sacrifice her to survive...)

“You're E-rank, right? How many stars do you have?”
"Mmh... I won't get any this time since I failed my mission, so forty-five."
"You're close to the graduation exam, then!"
"I... will not take it... I tried it a while ago but I failed. I can't use a sword..."
"You don't particularly need to be a good swordswoman to be a D-rank," Iris began. "Look at me, I'm pretty bad."
"Why do you sound so proud about this...?" Cyne asked, unable to bear listening to the novice who had started directly at D-rank. "Rina, don't listen to that idiot. You're vastly more experienced than her."

Rina shifted in her seat, blinking heavily.

"I-I might be less experienced at adventuring, but my point was that she can make up for her weakness at close combat with her magic. If she trains accordingly, I'm sure she can pass the next exam. Rina, I can teach you the fundamentals as long as I'm here. What do you think?"
"I..." Rina started, pressing a hand to her temple. She looked paler than earlier.

Noticing this change, Cyne immediately attended to her. "Are you okay?"
"I... I'm not," she managed to let out, her voice growing shakier. "Everything's spinning..."
"Iris. How much did you make her use up mana...?"
"I-I made sure to stop before the first symptoms of mana deprivation!" Iris defended herself. "I also showed her how to shut off the flow."

(And yet, it does look like mana deprivation... How come her condition worsened without releasing any mana since then...?)

Afterward, every subsequent little motion of the carriage seemed to drain more energy out of the beastfolk.
By the time they reached the city, the beast girl was so exhausted she could barely stand. Iris had her lie down on a bench while the others went with the guards. Currently, she had a glassy look in her eyes as if she was staring into a faraway horizon.

"It shouldn't be getting worse," Iris muttered, her brows furrowed. "That is not how mana deprivation works."

If Rina's mana pool was stable, her condition should have stagnated, whatever the amount of mana left in her body was. After triple-checking that the beast girl's mana veins were closed, only one possibility remained.

"Her mana is leaking out." 
"A... leak?" The best girl let out as she heard Iris mumbling to herself.
"It's as if you have been constantly emitting mana since we stopped our experiments, with you looking more and more mana-deprived."
"How... do I stop it...?"
"... You don't," Iris said as she uncomfortably averted her gaze. "Or rather, you can't. I've had the same condition since I awakened and I tried looking for ways to stop this flow, but I haven't found one yet. You're the first person I've met that has the same condition."

As a noble, though, Iris had a much larger mana pool than human commoners or beast men. Since the recovery rate was proportional to the total amount of mana, she only ended up metabolizing mana at a slower pace. 
As for Rina, however, it seemed her recovery rate couldn't keep up with the loss of mana.

To make things worse, unlike Iris, Rina lacked the control required to reabsorb her escaping mana. For a beastfolk, manipulating mana externally was challenging enough already. Combined with the neutralization, reclaiming her own mana became outrageously difficult.
As Iris calmly explained to Rina the situation she was in, the beast girl's face became even paler.

"W-why is it... happening to me?"
"I'm not certain but..." Iris began, her eyes downcast, "Whether you had this condition before or not, I'm responsible for your current state." 

Even if there always had been a leak, it had become a problem after Iris started the beastfolk's mana system, just like a small unnoticed leak would become an issue when one opened the faucet to the maximum.

"Will... I die?" Rina slowly asked as she looked into Iris' eyes for an answer.
"... I won't let that happen," Iris said firmly. "Sure, if we do nothing, you'll die. Even if we recover all your mana pool right now, you'll still die within a few days."
"..."
"There are solutions, however."
"... Solutions?"
"A mage could force mana in your body just like I did earlier. We shouldn't count on doing it manually, though. Do you know some healing mages of something?"

Seeing the beast girl weakly shaking her head, Iris could tell she was the loner type.

"I'm back!" Cyne exclaimed as he ran to the bench. "Iris, I've got what you asked for."
"Ah, thank you," she said as she looked into the bag he was carrying and retrieved a small bottle. "As for the other solution, here it is. Drink this."
"W-what it is...?"
"A mana potion. If the mana can't be brought to you directly,  you just have to generate it inside your stomach."
Rina gasped, eying the bottle hesitantly. "E-eh...? Aren't those expensive...?"
"They're indeed fairly pricey, from what I heard. Cyne, were you able to buy only five potions with my reward share?"
"I could only afford four," Cyne corrected. "The fifth one's on me."

After having inspected the bottle's contents despite her unfocused eyes, Rina glanced up at Iris. "Can I... really drink this...? You won't... force me to pay you back when I'm done?"
"I won't... Please, drink it," Iris insisted. "As I said, I'm the one who got you into this mess in the first place."
"Okay...", Rina said before gulping down one potion. "Ugh..." 

The beastfolk's nose crinkled at the bitter taste of the medicine. In only a minute, though, after having downed two potions, her complexion finally returned to normal.

"Will I be forced to drink these for the rest of my life...? I can't possibly afford them."
"Well... There's still the first method that involves having someone transfer mana directly to you..."
"Who would bother doing that for someone like me?" Rina sighed, her ears drooping.
"I would. If it's alright with you, Rina, come with us. Become a D-rank and join our party," Iris offered. "I'll even provide you with the best mana potions in the entire kingdom."

Before Rina could utter a response, Cyne, astonished by the impulsive proposition Iris had just made, turned toward her.

"Did... Did you just recruit her? Just like that? Without asking me...?"
"What was I supposed to do? Leave her to die here?"
"I mean, I did gather that her condition won't be solved right away, so I can understand why you would ask her to accompany us," Cyne said as he put everything together. He moved closer to Iris and whispered, "Do you need to recruit her in the party though...? To me, it looks like you're taking advantage of the situation because you're interested in her magic. In that condition even an accident?"
"That's... pretty rude of you to suggest I forced her hand," she whispered back indignantly. "I didn't want this, and I do feel miserable at the idea of making her abandon her life here..."

(But I indeed shouldn't pressure her too much when she's overwhelmed by the situation. I've been a bit hasty.)

Iris turned to the beast girl and cleared her throat. "For now Rina, just come to Phesiora with us. Whether you decide to join my party or not later on, I'll cover any expense related to your condition."
After a long pause, Rina met Iris' eyes and nodded slightly. "I'll come."