---

Doing nothing but flying all day got old fast, so even the kids had taken to learn Chess from Mark, and they all internalised the basics faster than Aaron did. It made him almost jealous. In an afternoon, it was as though they'd spent hours practising, and in less than a week, they provided an adequate challenge for Aaron.

A Strategy skill appeared halfway through the week. Still, it wasn't until the night of the third day, when Mark was explaining something he'd seen a grandmaster from his old world do that one time, did he get the notification they'd been waiting for.

Mark whooped his arms up, startling everybody, and Aaron couldn't help but join him. They'd been so close for days now it drove them crazy. When they told Ren their theory about Samir's strength, he seemed sceptical but encouraged experimentation nonetheless. He was meditating, but Aaron hazarded he'd be mighty interested when he came back.

Aaron read along as Mark gushed over his newfound skill, his eyes bulging at what he was reading.

(Rare)Teaching Lv 1: You've shown an uncanny talent for instructing people. Teaching skills, topics, and concepts you're intimately familiar with becomes almost second nature. Increases your student's learning speed by 50% when teaching a new skill. Bonus drops by half when teaching otherwise. Can only teach up to 50% of skill level. (1% increase in learning bonus per level and + 0.25 Mind every 5 levels.)

"Fucking finally," Mark grinned, laughing like a madman. Rubbing his hands together, he said, "now, we're cooking. Sokka! Come here. How'd you like to learn how to fight with a Baton?"

Sokka looked up from his spot across the campfire, where he was in a heated game of Chess with Katara, and looked hesitant.

"I don't know. I wouldn't want to leave Katara during a serious game."

"What if I told you Mark could make you better than you ever were with the sword in a week," Aaron said.

Sokka rushed to his feet, toppling the makeshift chess board.

"Hey!" Katara protested, but Sokka didn't bother looking her way.

"I'm tired of being the fourth wheel in every fight. Count me in."

What followed was one of the most disturbing displays Aaron had ever witnessed, yet he couldn't look away as watched as he watched Mark's new teaching skill work its magic.

Sokka went from a bumbling buffoon to standing in proper stance in an hour, and by the second hour, he could follow the Kata to a passable degree.

"Holy sheet!" Mark cackled, "I'm already at lv 3. Samir is going to get wrecked."

Aaron couldn't agree more. The skill was everything he'd expected and more. With it, the Air Nation could make him a whetstone, teaching him all of the most powerful skills of the Air Nation, and further fastrack his skill progress with the X2 learning speed cards, which he'd been hoarding for a week now if they could impart his knowledge into the ghosts, the rest of the gang, and Aaron, they'd be unstoppable.

Mark was already lv 28, Thanks to the nightly hunts. Together, they'd taken down two Saber tooth Lion Mooses and an Armadillo bear along with a small guarded supply caravan. He was coming up on his level limit, and it wouldn't be long before he had no other choice but to focus on his skill.

Sokka heaved on the ground at the end of the training session, staring at his hand in surprise. "How am I learning so fast?"

"You think that's fast? You ain't seen nothing yet."

Then, Ren stood up. He called Aaron and Mark to the side to congratulate them, a nearly imperceptible smile on his lips.

Mark shuddered at the sight. "Is he smiling?"

Aaron blinked at the sight, not quite believing his eyes. "I believe he is."

"You both do not understand the gravity of what you've just stumbled upon," Ren said, ignoring their comment. "It has the potential to revolutionise how we train ghosts and Phantoms. What takes years to master could be cut down to weeks. We could have an army of elite soldiers that could rival the Fire Nation in months, all possibly immune to Samir's techniques. Time might finally be on our side! Ha."

Unlawfully taken from Royal Road, this story should be reported if seen on Amazon.

Aaron was taken aback by his father's emotional outburst, and Mark grinned.

"Why don't you tell us how you really feel? I gotta say I think this newfound enthusiasm looks rather fetching on you."

Ren gave a deadpan look. "Needless to say, you'll have to redouble your training efforts and nightly activities. Grandfather and I would love to see the potential effects of the parallel processing skill you've talked about. I imagine the ability to process multiple complex thoughts at the same time would transform how you'd approach bending."

"No rest for the wicked," Mark said. "Well, Aaron, how would you like to help me figure this thing out."

"Gladly," Aaron smiled. His relationship with Mark had evolved from benign hate to blossoming respect over the past week. Despite Aaron's many reservations, Mark had technically not betrayed them yet, but that could be because of the lack of opportunity.

Still, Mark had been willing to meet him halfway, and that earned him the benefit of the doubt at the very least.

---

Parallel processing, as Mark described, was a powerful mental skill that allowed you to carry out multiple complex calculations and thought processes at the same time.

It had its basis in Multi-tasking, which every human was capable of to some degree, and Mark theorised they needed to sharpen that innate skill to a knife's edge, then tag on complex mental calculations on top to attain the all-powerful skill.

Together, Aaron and Mark came up with a series of exercises that required the utmost focus of both parties and progressively made things even more impossible until Mark attained the skill.

The first of a series of exercises was physical and mental.

Slowly shifting Chi through their limbs as they performed routine callisthenics.

The first session was positively dreadful. Aaron's head throbbed the entire time he performed a basic routine of pushups, pistol squats and pullups over and over again. Despite how overwhelmingly physical Chi proved to be, manipulating it was predominantly mental when the body did not flow with it.

It was like fighting with both hands tied behind your back. It was possible but needlessly painful.

They trained through the night, taking several breaks to rest up before they went back to ritual punishment. They abused his reinvigoration potion several times through the night to recover their strength and stamina. And by morning, Aaron's head didn't feel like it'd explode if he tried to manipulate Chi without moving his body, and Mark's wasn't turning purple as often.

Of course, he still chose to nap while Aaron straightened out camp and continued through his chores, counting down the days until his punishment was over. Aaron slept during the morning hours until Appa touched down for lunch.

Mark and Aaron spared as usual, but this time with a severe handicap. They maintained a mental game of Chess. Aaron dominated but held on by a knife's edge on both fronts, but Mark didn't look like he was doing any better either.

Aaron wove under a blow, his hip hinging as Mark's kick blurred past as he spun on his heel, transitioning to a low sweep to take Aaron off his feet. In response, Aaron sprang backwards and bounced on his hands before returning with a double kick and a chess move.

"Bishop to D7, Check."

Mark grunted as he crossed his arm to tank the blow and returned a high kick while yelling his counter.

"Castle to H7."

Aaron sidestepped the kick, lashing out with his foot and taking out Mark's leg from under him. "Queen to H7, Checkmate."

Mark grunted as he came tumbling down. "I can't believe you beat me."

Aaron smiled, panting even as his muscles screamed at him. He craved a recovery potion but stopped himself from going for it. "Like there was any doubt."

Mark pouted. "It's such bullshit. I've been trying to beat you since I was level 1, and I'm almost 30 now. If you're that high, how much higher are old monsters like your dad?"

"Level 80?"

"The numbers don't go that high up," Mark grumbled, and Aaron laughed.

"You might get stronger and faster every day, but power is no substitute for real experience. Until you've mastered your powers, I don't think you stand much chance. If it makes you feel better, neither do I."

Mark sighed. "No. No, it doesn't make me feel better."

Aaron laughed and rubbed his head while the younger boy batted his hand away.

"So, Chess?"

Mark nodded. "Chess."