For the purposes of this fic I'm interpreting Isono's position as involving bodyguard duties. I don't think his official title is ever explicitly stated.

Warnings: mild references to child abuse and violence.

Primary objective: protect the charge. All else is secondary. All other rules, all duties, all meant nothing if Seto-sama's health or safety was in danger.

Some nights, when Isono's boss Gozaburo was away on business or 'working late' with his secretary, the tight authority of the Kaiba Estate would slacken, the house would breathe freely for a few hours, and Isono felt as though he could finally do his job properly. It was difficult to protect his charge when Gozaburo seemed so set on putting Seto's health and safety at risk, denying the boy food and sleep and company until Seto's spirit shrunk so far into himself, withered so horribly, that Isono decided that if he let it continue he would be compromising his primary objective. And so, on these nights of quiet respite when Gozaburo wasn't around, Isono would shepherd the young Mokuba into his older brother's room for an hour before bedtime, and stand guard outside the door as he listened to the bedtime stories Seto-sama would tell his little brother.

Always the same premise: the princess, the dragon, the tower; you know how it goes. But there were deviations. Little shifts. In every retelling the story seemed to shake itself, settle itself into a slightly different skin. Isono wondered if Seto-sama was even aware of the alterations he made to his brother's bedtime story. The knight slowly faded from the story. The dragon became a protector, not an abductor. Princess and dragon both became trapped in the tower, and rather than planning an escape they would imagine adventures together, curl up as one and watch the window and dream of skies and infinity. And each other, forever.

Isono wondered if he had failed his primary objective simply by letting Seto-sama remain in his foster-father's house.

But he did what he could. If seeing Mokuba was significantly beneficial to Seto-sama's health, if it kept the dark expression that had started to take over Seto-sama's features at bay, then Isono would honour his primary objective to protect the charge.

He honoured it in the face of an official reprimand, two pay cuts, and then he continued to honour it even when it cost him his pension. By this time, Isono had already taken a bullet for Seto-sama – a rival company's assassination attempt, and Isono's bulletproof vest saved him from all but a broken rib – and Gozaburo was reluctant to replace him. Still, it was dissension, and Gozaburo did not allow for cracks in his empire, and eventually Isono faced the threat of termination. Only then did he shift his priorities. He could hardly protect his charge if he was fired and had to work as bodyguard to some meathead sportstar on the other side of Japan.

And that, the shift from the definite article to the possessive, that was the start of it all. Protect the charge. Protect his charge. Protect Seto-sama. Sometimes, when there was actual danger, such as when that assassin took aim and adrenaline reduced everything to cool, efficient calculations, the primary objective simply became protect Seto.

Strictly speaking, Isono's loyalties were to Gozaburo, since that was the man who paid his salary, but Gozaburo was not the charge. Seto was. Little Seto, fifteen years old and, as Isono was well aware, plotting his foster father's downfall. It was to him he aligned himself, and by his side he stood, protector and guardian in the wake of Gozaburo's suicide, even when most of the other security staff had been replaced or mysteriously disappeared.

Now, Isono's pay cuts had been healed, his pension returned, and he had been put in charge of KaibaCorp. security. The brothers could come and go as they pleased in the mansion with no threat of violence hanging over their heads for unsupervised meetings, but the bedtime stories did not make a reappearance. Anyway, at thirteen, Mokuba was probably too old for tales of princesses and dragons. He preferred the stories of gangs and gun fights that his video games could provide and gave Isono a very patronising look when he tentatively suggested asking his brother for a bedtime story like he used to.

"I really think nii-sama has more important things on his mind," Mokuba had said awkwardly when he realised Isono was serious, and then went straight back to his rather unrealistic game of computer generated violence. Isono had to admit he'd never been good with kids. Ironic, for a bodyguard trained in child-protection. He'd hadn't had much practice. Seto-sama had talked like an adult before he'd hit puberty and would order Isono around with an authority that rivalled that of his foster father.

Isono wondered, as he made his way to his employer's bedroom for the final check before he handed over control to the night shift, if anyone had ever read a bedtime story to Seto.

"The east wing?"

"Scoped and secure, Seto-sama."

"The west?"

"The same, Seto-sama."

Seto seemed to consider for a moment, looking up from his book that he was reading. "The back door? The front? The side doors? The ground floor windows? The vents?"

Isono hesitated briefly. "All checked and secure."

"Hn," said Seto, clearly dissatisfied. He lay on the bed, fully clothed in his usual modest, high necked black clothing. He didn't look like an eighteen year old, even when relaxing with a book in bed. What should have been a pose of relaxation just looked like another of guarded hostility.

"Is there a reason everything wouldn't be secure, Seto-sama?" Isono ventured. "You've never expressed this much concern before."

Seto continued staring into space for a moment before he lay the book spread open across his narrow stomach and closed his eyes, putting his fingers to his temples. To the press, to his associates, to a passerby on the street, the young Kaiba Seto simply looked pensive and cold. To someone who had stood by his side and protected him for eight years, he looked as though something vital had been drained out of him, as though he was wearing away.

"And if someone did break in?" Seto said finally. "If one of my security screwed up and someone infiltrated the house?"

Despite his disciplinary training Isono was unable to repress a frown. "Seto-sama, I assure you our security-"

"Say I'm speaking hypothetically," Seto interrupted. "Say this is all just theoretical. Someone breaks in. Then what?"

Isono considered. "It would depend where they broke in."

Seto twitched his head and eyebrows to his own large bay window, several dozen feet up from the garden it overlooked and quite impossible to breach. "That window."

"Seto-sama, that window is far too high-"

"Hypothetically, Isono." He cracked what might have been a smile. "Humour me."

Isono thought for a moment, assessing the room, going over his training, quickly appraising where Seto lay in relation to the non-existent intruder.

"The intruder enters that window by breaking or picking the locks," he began steadily, "caught as he does so on the two BIPRO night vision cams positioned on either side of it, immediately alerting Kazuya monitoring the live CCTV feed in the security room. Kazuya buzzes the nine security guards patrolling the property and the two closest to your room would head straight here while the others scoped the property for other possible intruders."

Seto's maybe-smile has progressed into an almost-definitely-smile. "And then?"

"And then the guard closest to your room, likely myself, would enter and first assess whether or not the intruder was armed and, if so, with what, and would then seek to disarm or shoot the intruder if it was possible or protect your body from any injury if not. If the former, and assuming the intruder is not yet dead, I would utilise my formidable skills in hand to hand combat to disarm said intruder and incapacitate him until my colleague arrived to assist me. If the latter, I would remain shielding you from any possible harm until my colleague arrived to kill or incapacitate the intruder."

Seto's expression is softer now, but he is definitely smiling. His eyes slowly begin to close. "And then?"

"And then," continues Isono, "we would look forward to a lengthy court case and plenty of unwanted press attention. Eventually our intruder would be prosecuted, we would upgrade our security system, and life would go on as normal." He pauses, not quite sure if Seto is still awake. "Assuming that I succeeded in defending your life, of course."

Seto's eyes have completely closed, the lashes resting still and dark against the skin with unfamiliar calm. They don't twitch, like they usually do when he sleeps, as his eyes roll wildly behind their lids while he mutters incomprehensibly, lost within the deep folds of one of the frequent nightmares he won't admit to having. Now, he just looks peaceful, a little more like the eighteen year old he's supposed to be. Less the objective, and more simply Seto.

Isono permits himself another smile. "Will that be all, Seto-sama?"

"Mm," is all Seto offers in return, on the edge of sleep.

Isono gives a smart bow, even though he knows Seto can't see it. He then hesitates before taking a silent step forward and carefully lifting the book from Seto's chest, marking it with the book mark on the bedside table and quietly placing it there. Seto's breathing has evened out. His chest rises and falls delicately. His sleep is a quiet sleep.

Isono takes the liberty of switching the lights off.

"Goodnight, Seto-sama."

I think there's a lot of potential for exploring Seto's character through Isono, given he seems to be his right hand man, so I'm sad there is so little Isono fic around. Plus, Isono's just adorable.