Just some things before this:
Rokurou is 37 at the beginning and 42 at the end.
Lu-ten is 18 at the beginning and 23 at the end.
Rokurou honestly doesn't know what he expected from Iroh's child.
Lu-ten is a kind-hearted boy with a friendly smile and shining eyes. He is there when you need someone, never judging, but speaking wise words. On the battlefield he has your back, mourning for the losses when he was too late.
It's digusting.
But, he thought and forced his lips into a smile, they need him.
"His son will join your group."
"You want me to gain his trust."
"I wouldn't eat that if I were you."
He watched as the boy jumped in surprise and then turned to him.
"Sir?"
"Amal's food is considered to be one of the deadliest weapons our army has to offer."
He took a piece of flesh from the bowl, trying not to grimace as his fingers got dirty, and bites a bit off. Immediately he started coughing, sending a pained smile to the crown prince when the fit was over.
"Here." he said and held out a nearly identical dish. "This may be a bit bland, but at least it won't kill you."
The prince took the bowl with a greatful smile and made space on the little bench. "Thank you, Sir."
"No need to thank me, boy." He offered his hand to the boy, having sat down, and smiled invitingly. "Rokurou."
The boy took it and laughed, a carefree sound that made him want to strangle the youth. "Lu-ten."
"He's annoying."
"Something you two have in common then."
It was a slow progress. Very slow.
Because, apparently, the boy was not a direct copy of his father.
No, the boy actually hid a rather moody side, which he became acquainted with as he got closer to him. One second he was the perfect little sunflower and in the next he was upset with you, because "you just don't do things like that."
It was like walking on eggshells and, when he first found out, he nearly had a laughing fit.
Because that boy was so much like him sometimes.
Maybe that was the reason he didn't have to fake his smiles to the boy anymore.
"Are you feeling something for the boy?"
"Are you jealous?"
Over the years their friendship grew stronger.
Or at least that's what Lu-ten was thinking. Rokurou, on the other side, was only waiting for the boy to spill the information.
Because he was getting impatient.
"What are you doing, princess?" he asked one evening, after finding Lu-ten bowed over a piece of paper, pen in hand.
"Writing my father. You know how he can be." The boy smiled, propably thinking about the geezer, and Rukorou saw an opening.
"Actually, no." He sat down next to him and chuckled. "You never really told me about him."
The shock was visible on the boy's face, but it was quickly replaced by a unusal sad smile. "My father is always worried about me, because of a accident in my childhood...it was the accident where my mother died. A assasin wanted to take my life, but my mother saved me, sacrificing her life in the process. Since then father preffered to be by my side, to protect me. So I write him letters to take some of that worry away, to let him know I'm still ok."
He took the boy in his arms and hid his triumphant smile in the dark brown hair.
Finally.
"Why didn't you think of that anyway? It's pretty obvious."
"Because I cannot comprehend how one's child can be so important. But I guess it is obvious, considering who it is."
"Rokurou."He looked around the battlefield and, after making sure that no living soul was near them, kneeled down next to the boy, taking note of the wound on his leg.
"Shhhhh." he whispered soothingly and gripped the knife in his pocket, pulling it out in one graceful movement.
He sat himself on the boy's lap, leaning forward until their noses nearly touched. He wanted those amber eyes to look at him. He wanted to be the last thing the boy saw.
"Ro...kurou?" Oh, the boy was terrified!
He smiled, knife pressing against a trembling throat and lips ghosting over the sweaty forehead. "You want to know why, don't you? Why am I betraying you, my best friend?"
He looked back into those eyes and continued in a whisper: "Oh, just imagine how broken your father will be! His poor son had to suffer, because he couldn't protect him. His poor son, all alone in his last moments, the wound the enemy had given him not killing him immediately."
He pressed a chaste kiss to those dark brown tresses and listened as the knife pierced skin and muscle, feeling blood run down his hand. "Sadly I'm not in the mood for explaining."
"My dear friend," he sat down next to the robed figure and poured the tea into two cups, a small smile playing at his lips. "Will you enlighten me as to what your next steps will be?"
"Become Firelord, of course." Ozai took a steaming cup and their eyes met for a brief moment. "Now that my brother's spirit is broken with the death of his only heir, it won't be a problem."
I have recently gotten into Atla and Lok and this is the result.
I apologize for every grammatical or other error.
Just some notes on ages at the end of this fic (again):
Rokurou: 42
Ozai: 42 (It's the year where he is made Firelord)
Iroh: 57
Lu-ten: 23
!This whole thing is just a Headcanon of mine!