After receiving a message from Sona asking for help with a certain mission, Goku left the party, teleporting to where Sona was located.
"I'm here, Sona," Goku said, appearing suddenly and startling Sona and Tsubaki in the Student Council room.
"Don't scare me like that, Goku!" Sona scolded him, her heart racing from the fright.
"How did you appear so suddenly without us noticing?" Tsubaki asked, still breathing heavily.
"Oh, this is a skill I learned a long time ago," Goku explained to the two girls, telling them how and when he learned the technique. They were amazed by the intense life this person had lived.
"Well, putting that aside, I called you because I need your help with a mission I was assigned," Sona said, changing the subject.
"But Sona, why don't you use your servants to complete the mission?" Goku asked, confused.
"This mission is too dangerous, and they aren't ready yet," Sona replied.
"If we had more power, we would go without hesitation, but..." Tsubaki said, frustrated by her lack of strength.
"Well, don't make that face. Power comes bit by bit, and you still have a lot of room for improvement," Goku said, placing a hand on Tsubaki's shoulder with a smile to ease her frustration.
"Thank you, Goku," Tsubaki smiled back at the Saiyan.
"Besides, if you make that face, Kiba would be sad," he added with a teasing grin. Tsubaki turned a bright shade of red.
Sona, watching this, could only smile for her friend, who began chasing Goku around the club room, annoyed and blushing.
"Then, let's get moving," Sona said seriously, and Goku nodded.
The two entered a magic circle and transported to a rocky wasteland. Nothing was in sight, but one thing caught Goku's attention: the crimson sky.
"Hey Sona, where are we?" Goku asked.
"We are in the Underworld," Sona replied, analyzing Goku's expression.
"Hmm... so this is the Underworld," he said, showing no reaction at all.
"You aren't surprised?" Sona asked, not seeing the reaction she expected.
"Actually, I've been to much stranger places," Goku said, remembering Hell and various planets he had visited.
"You are a very strange person, Goku," she said with a sigh.
The two walked in a specific direction. Goku found it odd that Sona seemed to know exactly where they were going without a map or help.
"Hey Sona, who sent you on this mission?" Goku asked.
"It was one of the Maou," she said without stopping.
"Maou?" Goku tilted his head in confusion.
"The Maou are the demon leaders of this place. To put it in a way you'll understand, they are the strongest," Sona explained.
This only made Goku excited. Hearing "the strongest" put stars in his eyes as he imagined incredibly powerful fighters.
"I don't know what you're thinking in that crazy head of yours, but the Maou aren't as powerful as you're imagining," Sona told the Saiyan, who didn't seem to hear a word she said.
After walking for a while, they reached their destination: an industrial warehouse in the middle of nowhere, guarded by armed devils.
"This is the place," Sona pointed.
"Ummm... I sense several energies. One group is devils, but the others seem to be human," Goku said, rubbing his chin.
"It seems those humans were kidnapped to be turned into slave devils and then sold by some high-class devils," Sona said irritably.
"Then let's go and finish this quickly," Goku said with a serious look. Sona didn't miss it; she blushed, having never seen this side of the Saiyan before.
With that said, Goku shot toward the guards without warning, leaving Sona with her prepared plan stuck in her mouth.
"Haa... he's so impulsive, but I don't dislike that," Sona said to herself as she watched Goku tear through everything.
Once inside, Goku guided them using his ki-sensing ability. They quickly reached where the kidnapped people were being held.
"Calm down, everyone. We are here to rescue you," Sona said in a reassuring tone.
"Now, step back for a second," Goku told them. The people moved away, and with a small blast of energy, he destroyed the magic barrier.
"Now try to stay together and don't separate," Sona instructed the crowd, who nodded frantically.
"Goku, you go ahead. If you see an enemy, take them out," the black-haired girl told the Saiyan, who nodded.
Everything went smoothly. Thanks to Goku eliminating everyone in their path, they were able to leave without trouble and bring the people to the transport circle Sona had created earlier.
As the rescue was nearing success, Goku sensed one more human energy.
"Hey Sona, it looks like there's one person left," Goku told her just as she was about to leave.
"Then let's go get them and get out of here before things get worse," Sona replied.
"Wait here, I'll get him quickly." Saying that, Goku placed two fingers on his forehead and vanished.
"What a convenient technique," she said with a half-smile.
In a room nearby, a young man with ash-blonde hair sat tied hand and foot. His name was Saji Genshirou. He had been kidnapped on his way home from school and was now waiting for the boss to turn him into a slave.
The guys guarding him seemed nervous about something, which terrified him; he didn't want them taking their fear out on him. But his fear was unfounded because, in that instant, a guy with gravity-defying hair appeared and took out the guards in a flash.
He couldn't believe this boy, who looked about his own age, could do something like that so easily. Goku approached him and untied the ropes.
"Take it easy, it's all over now," Goku told Saji.
"Tha-thank you," Saji stuttered, still in shock.
"What's your name?" Goku asked.
"Saji, Saji Genshirou," he replied. Goku extended a hand with a smile, and Saji took it.
"Nice to meet you, Saji. I'm Son Goku, but you can just call me Goku."
"Ah! I know who you are! You're the one they call the Guardian Prince of Kuoh!" Saji remembered. However, Goku didn't look very happy about that title.
"Haa... that name is embarrassing. Please don't call me that," Goku sighed.
"Sorry," Saji apologized to the depressed Goku.
"Well, it looks like you were the last one, so let's get going," Goku said.
With that, the two left the area using Goku's Instant Transmission.
Sona was waiting for Goku by the teleportation circle. She didn't notice a devil who suddenly launched a powerful magic attack at her.
Under normal circumstances, Sona could have dodged it, but she had been caught off guard. She closed her eyes, bracing for the impact.
But time passed and nothing happened. She opened her eyes to see Goku's face; he was looking at the devil who attacked her with pure fury.
She was stunned—not just because she had been rescued, but because Goku was carrying her in his powerful arms, "princess style," and they were floating in the air without any devil wings.
With a face redder than a sunset, she asked, "Goku... can you fly without using your wings?"
Changing his expression back to normal, he replied, "I could always fly. Didn't I tell you?"
"You never said anything about that!" Sona replied, exasperated. "Does Rias know about this?"
"No, the subject never came up," he said neutrally.
"Hehe, so I'm the first one to know," she thought, smiling like a girl in love.
Goku just looked at her with a raised eyebrow as he descended and set her down gently on the ground.
"Now, die," Goku said to the enemy devil. The devil didn't even have time to respond before being disintegrated by a powerful ki blast.
Saji, watching from a safe distance, thought he was either dead or dreaming given all the crazy things happening. He was snapped out of his thoughts when Goku and Sona called him to leave.
Back at Kuoh Academy, the kidnapped victims had already headed home. Only Sona, Tsubaki, Goku, and Saji remained.
"Well Saji, goodbye then," Goku said, but Saji said something that surprised everyone.
"I want to become a devil," he said seriously.
"Are you sure, Saji?" Goku asked.
"Yes. After everything that happened, I realized I'm weak. I need power to protect myself and those around me."
That answer brought a smile to the Saiyan's face. He patted Saji's shoulder and gave him a thumb's up.
"So Sona, what do you say about making him part of your clan?" Goku asked. Saji looked at her with hope.
Sona looked at Saji and Goku with a raised eyebrow, then glanced at Tsubaki, who simply nodded. With a sigh, Sona accepted. A happy Goku gave her a hug, making her blush furiously.
And that was how Saji became a devil and a member of the Sitri Clan.
FIN