Finally. After exactly three months, it is complete. Sometime, I'll upload my cheesy stick-figure plotting-art I did. When I get around to it.
This is for MostRemote who gave the prompt: unreciprocated Guardshipping (with Isono rejecting Kaiba because he thinks it's unhealthy).
It's so frighteningly me that I hope it's even close to what you wanted.
When a child is forced to be an adult, the child never really goes away. He just hides away, safe, while the adult protects him.
And, truthfully, Seto Kaiba was barely older than a child.
The adult Kaiba ran a company forcefully, ferociously, and with an almost vicious efficiency that was hardly seen in business peers three times his age.
The child Seto created amusement parks for children to be children.
The adult Kaiba had been trained, and further trained himself, in strategy and the ways to win at any cost.
The child Seto used this knowledge for trading card tournaments.
The adult Kaiba had a technical genius that far surpassed the inventors who, by rights, should have been teaching him.
The child Seto turned this genius to games.
The adult Kaiba was the protector, guarding his home, his life, and most importantly, his brother from anything and everything.
But the child Seto still longed to be protected.
And that is why he has Isono.
The adult Kaiba rationalized Isono's use to protect his body so Seto could protect what was his. He did not need love, just loyalty.
Which made that night that much stranger to the adult Kaiba's cold logic.
Seto was in his study, working feverishly at his desk, Isono standing by the window to his left, just as he had every night, just as they had every night for the past two years. This night should have been no different from all the others that had passed in this room, silent and content. Indeed, this night had been no different from all the others. There was no uncomfortable tension in the air, no change in routine, no sideways glance.
Perhaps that is what made the change so dramatic. So disconcerting.
So inevitable.
"Isono."
"Yes, sir."
"Read to me."
"What, sir?"
"Anything. Just pick a book and read it aloud."
"Yes, sir."
But choosing a book was a challenge. Seto's mood was odd, indiscernible. Something light and humorous? That might be seen as patronizing. Something satirical? Perhaps too cynical for this current mood. Something classical? That would be the safest choice. Nothing too dark, too heavy, but elegant and calming. Perhaps poetry.
"Isono."
He must choose.
Selecting a book, he turned back to Seto.
"Where would you like me to begin, sir?"
"Anywhere. Just read. Sit down."
Isono bowed and sat in the large chair in the corner. From his peripheral vision, he watched Seto sitting rigid in his chair and staring intensely at his screen, although perhaps not truly focusing on anything in front of him. As Isono found a place, he stole a full glance toward the desk, quickly assessing Seto's body language. Yes, he was stiff, tired perhaps, but there was something else. Something in his face, the curve of his mouth, the set of his eyes. Something Isono couldn't read.
It scared him.
From childhood's hour I have not been
As others were; I have not seen
As others saw; I could not bring
My passions from a common spring.
Isono broke off as Seto stood. Seto looked at him briefly, that strange expression still on his face.
"I didn't tell you to stop."
Isono nodded and continued. As he read, Seto walked to the window and looked out on the ground. His face reflected eerily in the glass, a pale half-visible specter.
And the cloud that took the form
(When the rest of Heaven was blue)
Of a demon in my view.
Isono looked up, waiting for further instructions. Should he continue? Should he stop? Should he read something else? Seto turned to him and stared. Just as Isono was about to speak, Seto crossed the room and fell to his knees, burying his face in Isono's lap.
Isono froze, confused and concerned. Seto was digging his fingers into Isono's thighs as though trying to test how tightly he could hold him, his shoulders tensing and relaxing every few breaths. He wasn't quite crying, but it was as close as he came.
"I can't do it," Seto said, his voice muffled. "I don't want to be weak." He took a shaky breath. "I am weak." He looked up at Isono.
"Take care of me."
Isono opened his mouth, trying to find something to say. Seto stood, towering over him, bracing himself on the chair. He leaned down and kissed Isono, awkward and desperate. He pulled back slightly, resting his forehead against Isono's.
"Take care of me," he whispered. He seemed barely able to keep himself from collapsing. "Take care of me."
Isono gingerly put a hand on Seto's shoulder; he was trembling.
"Sir." Seto made a pained sound. "Seto."
Seto pulled away and met Isono's gaze. His eyes were pleading for things he couldn't ask. For the first time in years, he looked like the teenager he truly was.
"Seto. I can't give you what you want. I won't give you what you want."
"Why?" His voice regained some of the steel it usually had.
"You don't know what it is."
Set stood up full, glaring down at him.
"I know exactly what I want." Isono stood.
"Then, what?"
"I want- I want... I... I want you to take care of me."
"I do."
"No. I want more. I want you... I want you to love me."
"No, you don't-"
"Don't tell me what I do or don't want! If I say I want to love you, then I do."
"You want to love me or you want me to love you?"
"I-" He collapsed in on himself, his face once again looking his age. "Isn't it the same thing?"
Isono took Seto's face in his hands.
"Seto. I can't stop you from loving me if you do, and you need to know that I care very deeply about you and I will protect you until I die. But I will not love you the way you want me to."
Seto started to pull back, but Isono continued:
"Until you learn the difference between love and obsession, anything you feel toward me will never be what you want. You still have some growing to do, but I will be here while you do it."
Seto pulled away and stared at Isono, his eyes searching the other man's face. Satisfied, Seto let himself fall into the older man's embrace. Isono may not love him yet, but he would be there until he did.
And that's all Seto wanted.