The long-awaited day of the Mark of Mastery exam had finally arrived. Tension filled the Great Hall as the masters and apprentices gathered to begin the testing. Master Eraqus and Master Xehanort occupied two of the three thrones at the head of the hall, engaged in hushed conversation. Below them, Aqua and Terra stood, their expressions reflecting a mix of nervousness and determination.

Ven and Sky, on the other hand, were brimming with anticipation as they waited for the exam to begin.

"Who's that?" Sky whispered to Ven, catching a glimpse of the golden-eyed man looking their way.

"I don't know…" Ven whispered back, stealing a quick, uneasy glance at the enigmatic figure.

At that moment, Master Eraqus rose from his throne, instantly capturing the attention of the assembled apprentices.

"Today, you will be examined for the Mark of Mastery," he began. "Not one, but two of the Keyblade's chosen stand here as candidates, but this is neither a competition nor a battle for supremacy- not a test of wills, but a test of heart. Both of you may prevail, or neither. But I am sure our guest, Master Xehanort, did not travel all this way to see our youngest prospects in years fall short of the Mark."

Eraqus glanced back at Xehanort, who motioned for him to continue.

"I trust you are ready?" Eraqus asked.

"Yes!" Terra and Aqua replied.

Summoning his Keyblade, Master's Defender, Eraqus conjured five radiant balls of white light, signaling the start of the exam. As the two Keyblade wielders prepared to strike, the light flickered erratically, darkness beginning to consume them. Suddenly, a stray ball of light careened haphazardly towards where Ven and Sky were standing.

"Sky! Ven!" Terra and Aqua exclaimed.

Summoning Wayward Wind, Ven slashed through the ball several times, successfully destroying it.

"Don't worry about us! You two focus on the exam!" Ven called out.

"But you're in danger here! Go wait in your rooms!" Aqua demanded.

"No way! We've been looking forward to this - seeing you two become Masters! We're not gonna miss it now!" Ven retorted, readying Wayward Wind once more.

"Go sit with the Masters," Ven directed to Sky.

Sky nodded and dashed to the thrones. Avoiding Xehanort's watchful gaze, she took her place at Eraqus' left side.

"Are you alright?" Eraqus asked. "If this becomes too much, you are free to leave."

"I'm okay," Sky shook her head. "I want to see what happens."

Eraqus nodded and turned his attention back to the trio, observing as they effortlessesly sliced through the orbs. Despite this test being meant for the future Masters, Ven held his own in battle. Similarly, Terra and Aqua had no issues with the orbs, unleashing magic and shot-locks when needed. The orbs were quickly vanquished, signaling the end of the first trial.

"That was unexpected…" Eraqus noted as Ven walked back to his spot. "But one must keep a still heart, even in the most trying of circumstances. It was an excellent test, one I chose to let unfold. Which brings us to your next trial." He motioned for Terra and Aqua to face each other. "Now, Terra and Aqua, the two of you will face each other in combat. Remember, there are no winners - only truths, for when equal powers clash, their true nature is revealed."

Terra and Aqua readied their Keyblades, waiting for Eraqus' signal.

"Begin!"

The two apprentices lunged at each other, Keyblades clashing. Pulling back, Terra deflected Aqua's attacks before launching a powerful attack of his own.

Gracefully dodging, Aqua aimed for an opening and struck back.

Sky watched in awe. She had watched Terra and Aqua spar before, but this time felt different. She could see the determination in their eyes. They had prepared for this exam for so long, and now their efforts are finally paying off.

Terra leaped back, narrowly dodging one of Aqua's attacks, frustration etched on his face. As he readied himself again, darkness surged from his arm. In an instant, the once tall brunette's hair turned a striking silver, and his eyes gleamed with golden intensity.

Sky blinked, confused at Terra's sudden transformation. Blinking again, Terra returned to normal, leaving Sky puzzled.

She stole a quick glance at Eraqus, wondering if he noticed the change, but his expression remained unreadable. Sighing, Sky returned her attention to the match.

After exchanging a few more blows, Eraqus ended the match, satisfied with what he had seen. Sky hurried back to Ven, leaving Eraqus and Xehanort to confer.

"Hey, Ven? Did Terra look kind of weird when he was fighting?" She asked.

"Weird?" Ven thought for a moment. "No, he looked the same as always."

"Oh," Sky replied, disheartened.

"You're probably tired," he said, ruffling her hair. "You did stay up late."

"Probably," Sky laughed, shrugging off her concern.

Rising from his throne once again, Eraqus addressed Terra and Aqua.

"We have deliberated and reached a decision," he began. "Terra, Aqua, you both performed commendably. However, only Aqua has shown the Mark of Mastery."

"Terra, you have failed to keep the darkness within you sufficiently in check. But there is always next time… That is all."

As Xehanort made his way out of the room, Eraqus turned his attention to Aqua.

"Aqua, as our newest Keyblade Master, you are entitled to certain knowledge. Please wait here for further instruction." Giving a final nod to his apprentices, Eraqus swiftly made his way to the hallway.

"Hey…" Aqua started, turning to Terra.

Ven and Sky rushed to the pair.

"Terra, I'm sorry…" Ven said.

"Terra?" Sky asked.

Terra looked at the ground, dejected.

"The darkness… Where did it come from?" Terra wondered out loud. "Sorry… but I need some time alone." Bidding his friends goodbye, he left the room, dispirited.

"Is he gonna be okay?" Sky asked. She had never seen Terra so sad. Frustrated, maybe, but never sad.

"Terra will be fine."

The three remaining apprentices turn to Eraqus as he re-entered the room.

"Give him time to think. Terra will come around soon enough," Eraqus added. "Ven, Sky, you are dismissed. Aqua and I have much to discuss."

"Yes, Master," Ven and Sky bow, leaving Eraqus and Aqua to converse.

'The boy has potential…' Xehanort thought as he walked down the hallway. 'He just needs a little push…'

Xehanort smiled to himself. His plan was coming together nicely, and Eraqus was none the wiser. The pawns were falling in place. All he needed to do was make the next move.

"Vanitas," Xehanort called out, rounding the corner. "What do you make of Ventus?"

A boy dressed in striking red and black leaned casually against the wall, a black helmet resting at his hip. A look of boredom plastered on his face, unbothered by his master's sudden approach.

"He ain't gonna cut it," the boy scoffed. "Somebody's gotta break that loser in."

"Not here you won't," Xehanort warned. "I have to keep up appearances."

Vanitas pushed himself from the wall, placing the helmet on his head.

"I know that. He just needs a little incentive to leave home," Vanitas said, amusement coating his voice.

Xehanort sighed. Vanitas was strong but reckless. He would have to keep a close eye on him to ensure that he doesn't push Ventus too far.

"And the little girl?" Vanitas asked. "Is she the one you're looking for?"

Xehanort nodded.

"The power is there, but it's weak. It will be difficult to get near her with Eraqus here."

"Do you want me to take care of him?" Vanitas asked.

"No," Xehanort said sternly. " You have your mission. Go oversee Ventus. Don't go overboard. We need him."

"Yeah, yeah," Vanitas replied dismissively. "I'll make sure he's ready."

Turning on his heel, Vanitas stalked toward Ventus' room.

Sighing once more, Xehanort made his way to the courtyard, ready to begin the next part of his plan.

About an hour had passed since Eraqus had dismissed Ven and Sky from the Great Hall. While Ven had chosen to retreat to his room, Sky opted to study in the library. Currently, she was flipping through the pages of a basic spell book Eraqus had given her.

'To successfully perform magic, one must learn the fundamentals of each element,' his words rang in her head. 'A strong grasp of these concepts will allow you to perform powerful spells.'

Sky sighed as she read through the section on water. While she was grateful for the book, it was a complicated read for someone her age.

'Mpemba Effect - the phenomena where hot water freezes faster than cold water.'

'Pure water has a neutral pH of 7, which is neither acidic nor basic.'

'Water is the second most common molecule in the universe…'

'Water should be gas at room temperature…'

*Ding, ding, ding*

Sky jumped at the sudden noise.

'What is going on?' She thought, rising from her desk and making her way to the hallway. In all her time in The Land of Departure, she had never heard the bell ring.

As she was closing the door behind her, Ven charged down the hall, nearly knocking her over.

"Ven?" Sky called, barely avoiding a collision.

Ignoring her, Ven continued to the forecourt.

"Ven, wait!" She called again, running after him. Once outside, they spotted Terra slowly walking toward an open field.

"Terra!" Ven called out.

"Huh?" Terra stopped, turning to face him.

Ven came to a halt, stumbling forward when Sky ran head-first into his back.

"Ouch!" Sky rubbed her forehead. Quickly reorienting herself, she moved from behind Ven.

"Terra, what's going on? Are you leaving?" She asked.

Before he could answer, Ven cut him off.

"Terra! I... I..."

"It's okay," Terra smiled, ruffling Ven's hair. He turned to Sky. "I'll be back soon."

Turning away from the duo, Terra crossed the open field until he reached its center. He tapped his shoulder piece, and in a flash of light, his red and gold Keyblade Armor materialized around him. Summoning Earthshaker, Terra shot a blast of light into the sky, opening a portal to the Lanes Between. As the portal crackled with energy, he hurled Earthshaker upwards, transforming it into a sleek glider.

"Whoa!" Ven and Sky stared in awe. They had seen Terra and Aqua practice on their gliders a few times, but the sight never failed to amaze them.

Terra nodded at the pair before hopping on his glider and vanishing through the portal.

"Where do you think he's going?" Sky asked eyes fixated on the portal.

Disappointment plastered on his face, Ven stared after the older Keyblade wielder.

"Ven?" She called, pulling her eyes from the sky.

Briefly looking over his shoulder, Ven activated his own shoulder piece, donning his light gold and blue armor. Copying Terra's movements, he summoned Wayward Wind, transforming it into his glider.

"Wait!" Sky exclaimed. "What are you doing?"

Ignoring her protests, Ven jumped onto his glider and took off into the sky.

"Wait! Ven!" A voice called out.

Startled, Sky whirled around, spotting Aqua and Master Eraqus descending the castle steps.

"No! He mustn't!" Eraqus exclaimed and turned to Aqua. "You have to bring him back!"

"Don't worry, Master!" Aqua said, quickly transitioning into her black and dark blue armor. Like the pair before her, she flung Rainfell, transforming it into her glider. Climbing on, she swiftly rode into the portal after the two boys.

Sky watched as Aqua vanished into the portal, which flickered briefly before disappearing.

"Master?" She asked, turning to him. "Did something happen? Are they going to be okay?"

Eraqus let out a heavy sigh, his furrowed brow revealing his deep concern.

"Yes, child," he replied, his voice soft. "They can take care of themselves. Now come, we have quite a bit of training to do."

"Yes, sir!" Sky perked up and skipped back to the castle, her mind still lingering on the events that had just transpired.

Eraqus watched her go with a faint smile, but his thoughts were elsewhere. Despite his faith in his apprentices' abilities, a sense of dread gnawed at him. He wasn't sure what was going to happen, but it was best to start making preparations for what lay ahead.