Water was the best element to experiment with for Nathan. He could shape it into anything he wanted, make it move any way he wanted, and after getting the hang of transforming it from water to ice and vice versa, it pretty much became his number one element. Turning water into mist or steam was a bit more finicky than he thought, but he got the gist of how to do it after a few minutes of practice.
It helped that Roku's way of training him in waterbending was in the form of a water fight that ended up in the middle of the lake. He lost, of course. Miserably. But he enjoyed this form of training the most out of all the others.
As Nathan spun and diverted a torrent of water back at Roku, his arms began to fade away. "Damn," he said in disappointment. "Looks like I have to leave, Roku."
"It seems so," Roku said. "However, that was an incredibly productive session. Next time, we'll be training your fundamentals."
"That's fine with me," he replied, filled with anticipation for his next training session. "I'll see you next time."
After blinking once, he returned to his room. Without a candle, darkness filled the space. He could still see after his eyes adjusted to the darkness, but he definitely didn't have night vision.
'Now, what to do…?'
He opened his window, letting the moon's light illuminate his room. He gazed at the multiple sources of light past the mansion's walls and shrugged.
'Guess I'll go sneaking out again.'
It had become Nathan's favorite routine at night. These nightly strolls of his acted as his stealth and espionage training because he had to be careful not to get spotted by anyone. And while everyone else in the mansion was still asleep, he decided to make the most of his time and thoroughly explore the surroundings, gathering information such as where the guard posts or possible escape routes were.
Jumping from his window, Nathan silently landed on the grounded before swiftly progressing forward.
-=-
"That's it. Make sure you're twisting your hips and putting the weight of your body into each punch. And don't forget to keep your hands loose before tensing at the end of a punch. Both of you still seem to forget doing that," Nathan instructed, watching as Zuko and Azula performed the drills he taught them.
For the past three weeks, he only taught them the basics of boxing for an hour and a half each day ever since the wager. While they whined and complained about it, Nathan didn't budge. Speedrunning through the basics and moving onto advanced things like combos or counters immediately was a flaw he had seen too often in sparring partners and people he competed with.
Just as he expected, Azula picked up the basics pretty quickly, while Zuko was only barely able to keep up with her. It wasn't because the boy wasn't talented. He was. But it was clear to Nathan that Azula was the more ambitious and athletic of the two. For now, at least.
"Zuko, stop getting distracted! Focus on your drill!"
"Yes, sir!"
Nathan shook his head at that and now knew why he recently felt way older, despite him being only half a decade older than Azula at most. They were treating him like one of their old instructors.
After watching them train for another ten minutes, he noticed them becoming more sluggish.
"Alright, stop! Let's take a ten-minute break."
"Finally!" Zuko gasped in relief and rested on the ground. Azula wordlessly joined him. "Why aren't you also taking a break? You've been doing that the whole time!"
"Me? I am," Nathan calmly said as he maintained his position. He had previously been doing one-armed handstand push-ups, but now he was just holding it, tilting his body diagonally while also keeping it rigid. "This is me taking a break."
Truthfully, he was just bored, and this was his way of messing around. On the other hand, it was also a good way to train his balance.
"How are you even doing that…?" Azula asked, tilting her head. "Does it not hurt your shoulder to hold that position for so long?"
"No, not really."
"You always do these difficult exercises, but you never tell us how to do them. Can't you teach us?" Zuko asked.
"To do this, you need excellent physical conditioning, lots of practice, and near perfect balance. For you two, you're gonna have to work your way up from the easier exercises. I know you can already somewhat do handstands, but you guys already have your hands full with your firebending training and martial arts training. We'll do the physical conditioning when you guys get older."
"How much older are you talking about?"
Nathan exhaled as he slowly switched to the other hand. "You have to at least be… ten years old."
That was also the age he started doing proper calisthenics.
"Aww. My birthday's still a few months away…" Zuko said disappointingly.
Nathan turned to Azula. "What about you, Azula? When is yours?"
"Mine is a few days after Zuzu's," she said with a shrug of her shoulder.
Nathan made a mental note to get them something for their birthdays. He could come up with a gift to give Zuko, but Azula was the trickier one. He didn't know what she would like. Dolls were definitely off the table, though.
"What would you two like for your birthdays?"
Both of them paused in thought before answering, and Nathan observed Azula more closely. The girl began to act a bit differently after his discussion with her. She was more polite and courteous to him, and she didn't mess with Zuko as much as before. She also was more reserved around Ozai than he expected, and the father himself seemed to find it strange.
"I… don't know," Zuko said after thinking for many minutes. "I guess I'd like it if Uncle Iroh came back, but he's still leading the fight against the Earth Kingdom."
"Do you really want that kookie uncle of ours to come for your birthday?" Azula asked, scoffing. "You're ridiculous."
'Aaand I stand corrected,' Nathan thought with a sigh.
"Well… yeah. I like Uncle Iroh," Zuko answered unsurely.
"Of course you do."
Zuko frowned in irritation. "Well, what about you, huh? What do you want for your birthday? I bet it's something absurd again. You asked dad for a tigerdillo last time."
Crossing her arms, Azula turned her head away arrogantly. "Hmph. What I want is none of your business, Zuzu."
"Why you—!"
"Okay, okay! Settle down, you two," Nathan calmly said as he smoothly went back to a sitting position. "You barely fought in the past three weeks, so I thought things were fine, but clearly, they're not. Siblings should be caring about each other, even if it's in… roundabout and rough ways. And if you two are going to be learning from me, I want you two to be getting along with each other. We can't have a conductive learning environment if you two start getting into fights."
"She started it!" Zuko pointed at Azula agitatedly. She stuck her tongue out in response, which just incensed Zuko even more. "And how am I supposed to get along with her? She hates me!"
'That's a bit of an exaggeration, but he asked a good question…' Nathan scratched his head as he started thinking of a solution.
Azula's smug expression faltered for a brief moment at Zuko's words, a flicker of something unreadable crossing her features before she schooled her face back into its usual stoicism. Nathan caught the change and mulled to himself. Maybe this 'getting-along' thing wouldn't be so impossible after all.
"Alright, listen up," he began, his voice firm but gentle. "I understand you two don't exactly see eye-to-eye, but constant bickering achieves nothing. Maybe…" he trailed off, considering his next words carefully. "Maybe you could find something you both enjoy doing, even if it's separate activities. At least then, you'd have something to share and talk about besides arguments."
Zuko looked thoughtful. "Like what?"
Nathan shrugged. "Who knows? Maybe you could spend some time with Uncle Iroh… virtually, of course. You could write him a letter, tell him about your training, and ask him about the war."
Zuko's eyes lit up. "That's a good idea! Maybe he could even tell me some new firebending techniques!"
Azula snorted, but Nathan saw a flicker of interest in her eyes. "And you, Azula? Any hobbies you secretly enjoy besides… tormenting your brother?"
Azula's lips twitched, a hint of a playful smile battling with her usual glare. "Perhaps some… strategic board games? Father always thinks they're a waste of time," she admitted.
'This is just my guess, but Ozai probably thinks that way because Iroh likes playing Pai Sho. It's a bit far-fetched of a guess, though.'
A grin stretched across Nathan's face. "Perfect! Maybe you two could challenge each other sometime. A little friendly competition never hurt anyone. Give me one day. I'll be able to make a board game for you guys."
Zuko's initial enthusiasm dimmed slightly. "Challenge Azula? In a board game? I don't know… she probably cheats."
Azula's eyes narrowed. "As if you wouldn't, Zuzu."
"I'm not a cheater!"
Nathan held up a hand, silencing them before they could erupt into another squabble. "Look, I'm not saying you two have to become best friends overnight. But maybe, just maybe, you can find a way to tolerate each other. Who knows? Maybe someday you'll even find something you genuinely enjoy doing together." He winked. "Besides fighting each other, of course."
The tension in the garden seemed to dissipate slightly, replaced by a cautious curiosity. Zuko and Azula exchanged glances, a silent question hanging in the air. Perhaps, just perhaps, this 'getting-along' thing wasn't entirely out of reach.
'The fact that Azula didn't brush off my suggestion and actually added to it is definitely a good sign.'
-=-
"How were the kids?"
Nathan paused and looked up from the cutting board. Cooking for himself was a necessity of his before to keep his body fit and healthy, but now it was a small past-time of his and it helped to organise his thoughts whenever he did something monotonous. Talking to the chefs definitely helped with his repertoire of recipes, though. All the other ones he learned before were protein and nutrition focused, so most of them used similar ingredients.
"Oh, hey Ursa. Zuko and Azula were fine," he said, smoothly cutting the cooked meat into perfectly symmetrical pieces and placing them onto the oiled up wok with fried rice. He began tossing the rice skillfully. "They fought for a bit, but after talking about it, they came to a compromise."
Ursa's eyes lit up with interest. "That's… somewhat hard to believe."
"You can say that again," Nathan chuckled. "I've seen those two argue before, and they almost never come to a compromise. Seriously, I haven't seen two siblings fight as much as those two."
Ursa chuckled, covering her mouth with a sleeve.
"Like you said before, they can be quite rowdy. What did they decide on?"
"Well, Zuko thought it would be nice to exchange letters with their uncle from time-to-time. Azula suggested a strategic board game they can compete in."
"A board game?" she asked with a tilt of her head in the same way as Azula's.
Nathan smiled at their resemblance to each other. "Yeah. A board game. Speaking of which, is there a way for you to get me some wood and woodcarving tools? I'm planning on making the board game myself."
"Hmm. That shouldn't be a problem. I'll have a servant deliver them to your room."
"Thanks, Ursa," he said, taking the wok off the flame and setting it down. "Also, do you need me for something? You're usually with Zuko at this time of day."
"…You're right. I got sidetracked." She cleared her throat. "Piandao has arrived. He's currently in the garden with Zuko."
"Oh, he's here already?" He looked at the massive portion of food he had cooked. Sharing the food he made for himself was a bit saddening, but if it could give a good first impression with the Fire Nation's number one swordmaster and bladesmith, he wouldn't mind as much. "Hmm. Tell them that I'll be bringing a small meal. You and Azula are welcome to join as well."
-=-
As Nathan brought the tray of beef bowls and water to the dining room, he paused just outside when he noticed he became the topic of conversation.
"Lady Ursa, who is this young man you want to introduce to me?" said Piandao, his voice deep and gravelly.
"His name is Nathan. He's currently my children's martial arts teacher."
"How interesting," he said. "I don't recall them having a martial arts teacher the last time I came. This young man must truly be a martial artist of great skill if Prince Ozai appointed him as his children's teacher. He would have acquired one for them years ago if he had deemed it necessary."
"Without a doubt, Nathan's prowess as a martial artist is something that would leave many people in awe."
"Is that so? You speak of him with such respect that I can't help but look forward to meeting him myself."
Taking that as his signal, Nathan drew in a deep breath and put on his best smile.
"Sorry I'm late," he said, entering the dining room. Striding towards the table, he put down the tray of food and noticed the eye-catching sword sitting next to Piandao.
"Ah, and you must be Nathan," Piandao said, taking a whiff of the food's aroma. "Ursa didn't tell me you were an excellent cook as well."
"I'm a man of few talents. Cooking just happens to be one of them." Nathan humbly said, respectfully saluting to Piandao. "It's an honor to meet you, sir."
"Ursa tells me you're here to seek my guidance, but she didn't really specify on what. Could you elaborate for me?" Piandao said, looking at Nathan expectantly.
"Right." He sat down across from Piandao. "Well, to put it simply, I have too much time on my hands. Time I don't know what to do with. I was hoping that you would be able to help me in that regard."
Piandao had a look of surprise on his face before entering a bout of laughter. Nathan and Ursa exchanged worried looks.
"My apologies. It's just that it was the last thing I expected to hear. People would usually come to me seeking my tutelage in swordsmanship or bladesmithing, so this is a first." He continued on after calming down. "Truly, this has been an interesting day for me… But yes. I think I can assist you, young man."
Nathan and Ursa simultaneously breathed a small sigh of relief and exchanged smiles. He saluted to Piandao once more and said his gratitudes.
"By the way, where's Zuko?" he asked. "I thought he'd be joining us."
"He's currently practicing a set of sword stances in the garden," Ursa said.
"We made a deal. If he's able to perform the new stances to my satisfaction after one hour, I will personally forge for him a set of dual swords on his thirteenth birthday," Piandao added.
"Woah…" Nathan gasped.
'Now I know where Zuko probably got his first set of swords from.'
-=-
Author's Note: That last bit isn't part of official canon, only the fact that Zuko learned how to fight with dual broadswords from Piandao.