The Ilmark Palace in southwestern Ridill had once been built at extravagant expense by a hedonistic member of the royal family, and every inch of it was adorned with lavish decorations.
Slowly raising one's gaze from the scarlet walls revealed a magnificent ceiling mural framed in golden molding.
Painted in delicate colors were the founding king raising his sword against an evil dragon and the seven Spirit Kings blessing him.
Tonight's event in such a lavish venue was a masquerade ball.
Elegantly dressed gentlemen and ladies concealed their true faces behind masks, assumed false names, enjoyed a thrilling night, and sometimes even lost themselves in a one-night romance without revealing their identities.
At a table laden with food in a corner of the soirée, a man had claimed a spot and was enthusiastically stuffing his face.
"This is delicious. Hey, Sparkles, make it for me next time."
"I believe I told you my pseudonym, didn't I? Mister Alexander?"
"Forgot."
Saying that, the tall, black-haired man──Nero, disguised as a human──gulped down ham-and-vegetable aspic as though it were a drink, then licked his lips.
"Still, this mask is a nuisance. It makes eating difficult."
To suit the masquerade ball, Nero was wearing the formal attire Isaac had prepared for him.
His black formal attire was made from an elegant fabric that looked faintly purple in the light, and it suited Nero's tall frame perfectly.
The mask covering his eyes was scarlet and edged with gold thread, and because his formal attire was subdued, it looked all the more striking.
But Nero seemed to dislike the mask intensely, and he was scratching irritably at its edge with a claw. The sight reminded Isaac of Nero in his cat form, and Isaac had to suppress a laugh.
Like Nero, Isaac was also wearing formal attire and a mask. His attire was dark navy with minimal decoration, and his mask was a subdued black.
"You eat a lot."
As Isaac watched Nero devour his food, Nero speared a fried fish-paste dumpling with his fork and nodded cheerfully.
"Human cooking is interesting. I don't much care for fish, but I kind of like these things when they're mashed, rolled up, and fried. Rana brought me some before, but those had a different seasoning and were delicious too."
"You remember Miss Collette's name? You never remember mine, even after all this time."
Isaac looked at Nero with a gentle smile tinged with the faintest hint of reproach.
Nero, however, acted as though it had nothing to do with him.
"When Monica was at the academy, the name she said most often was Rana's. The second most-mentioned was Chilly, and the third was Loudmouth."
"What about me?"
"Of course I'd mention you. You're the one I'm guarding, after all."
"...I see."
In other words, Isaac had apparently only ever been mentioned as the person Monica was guarding.
Isaac had suspected as much, but gave a wry smile and popped a fried fish-paste dumpling into his mouth as well. It was not that he particularly liked them, but Nero seemed to enjoy them, so Isaac decided to remember the seasoning.
When dealing with Nero, food was the best bait.
"You have the same sense of taste as humans, don't you?"
"I don't know if it's really the same as a human's. But most of the things you make taste pretty good."
"That's an honor. But..."
Isaac broke off and glanced sideways at Nero.
"You don't actually need food, do you?"
Nero stopped moving his fork and blinked his golden eyes behind his mask.
"...You noticed?"
"If you were getting nutrients from food, that amount would be nowhere near enough."
There were a few herbivorous dragons, but dragons were generally considered omnivorous.
But that was only true of lower dragons.
"I once read a paper that said, 'Higher dragons are by now entirely different creatures from lower dragons and could even be said to be closer to spirits. What higher dragons need to sustain life is not food, but magical power.'"
That paper, written by a certain magical-creature biologist, had been dismissed by the academic community as an absurd delusion and had become notorious for all the wrong reasons.
But as Isaac observed Nero's behavior, he had begun to feel that the paper might actually be correct.
Nero loved eating and consumed a wildly disproportionate amount for such a small cat, but it was nowhere near enough considering the size of his true body.
Monica paid little attention to eating and did not seem particularly concerned, but Isaac had a perfect grasp of the food situation at her home and had long felt that Nero's food intake was strange.
"At first, I thought you were scavenging through the city's trash when Monica wasn't looking..."
"Wait. You thought I was scavenging leftovers?!"
He had.
If Nero, in his black-cat form, proudly told him that he had fought a stray dog in Sazandoll, it seemed only natural to assume that the fight had been over scraps.
When Nero glared at him, Isaac very naturally looked away and continued speaking.
"I understand spirits because I have a contract with one myself. Spirits can't maintain their existence unless they're in an environment with a certain concentration of magical power... It seems that purity is particularly important."
Magic in environments with a high concentration of magical power is generally highly pure. That highly pure magic is absolutely necessary to maintain a spirit's existence.
Therefore, spirits active in human settlements, where the magical concentration is low, form contracts with humans and maintain their bodies by receiving highly pure magical power through spirit stones.
Put another way, spirits are beings that can live only where the air is clean, and the spirit stone used for a contract is like a filter that cleans the air. The contractor, in turn, is like the one who maintains that filter.
Isaac's theory was that this rule applied somewhat differently to higher dragons.
"A higher dragon like you doesn't need food, but you do need magical power to sustain your life. Unlike spirits, you don't need high-purity magical power, though... Am I wrong?"
In response, Nero gulped down the fried dumpling and nodded.
"Well, more or less. I'm way more incredible than those frail spirits. Worship me."
In other words, food was not necessary for Nero's survival. It was merely entertainment.
His declaration, 'I'm hungry. I want food!' was essentially no different from saying, 'I'm bored, pay attention to me.'
"...By the way, if you tell Monica about this..."
"Don't tell her, okay? Once she realizes I can live without food, she'll seriously stop preparing anything for me."
Monica was not a heartless girl, but she did have a tendency to become overly rational from time to time.
She was better now, but she had once gotten by on nothing more than nuts and water, even for her own meals.
"That's true. If you periodically make a fuss about being hungry, Monica might remember that food is necessary too."
As he murmured his agreement, Isaac remembered the final sentence of a paper he had once read.
The maverick scholar of the Society of Magical Biology who had published a paper on higher dragons had concluded it with the following:
──Now that the world's magical concentration is gradually diminishing, spirits and higher dragons that require magical power will eventually decline and face the threat of extinction.
(It was a fascinating paper, but... what a shame. That paper will never see the light of day.)
As he quietly mulled over the contents of that paper, Isaac happened to overhear a conversation between some ladies nearby.
"Hey, have you heard that rumor?"
"The one about Prince Felix secretly attending a party hosted by Mrs. Megan?"
"Yes, that one. Mrs. Megan is hosting tonight's party too, so he must be here."
To keep himself out of the gossiping ladies' line of sight, Isaac casually hid behind Nero.
Isaac had not attended this masquerade ball to enjoy the food or to seek a night of romance.
"Well, let's take care of business soon. Mister Alexander, could you lend me your strength?"
"I'll drink my way through all of these first."
Saying that, Nero began a drinking contest with the various glasses.
Isaac took the glass from Nero's hand and returned it to the table.
"Once we return to the estate, I'll prepare as much alcohol as you want."
"Make it strong enough to burn my throat."