Songs in the Void

Hub World, Earth, Japan, Tokyo. 

After texting his address to Chiho, Tatsuo sent a text to the previously mentioned girl surnamed Tsukamoto. And that caused the smartphone of a fair-skinned, teenage girl with shoulder-length black hair, bangs that cover her forehead, red eyes, and a slim, yet curvy figure living in a traditional Japanese house to stop working on her homework to check the alert she just received. 

"Hmm? Soramoto-Kun?" The girl, Tsukamoto Yakumo, mumbled after picking up her phone and checking the notification. "I'm pretty sure this is the first time he's ever texted me." 

With that, Yakumo opened Tatsuo's text. And when she read it, she could not help but open her eyes a little wider. 

Soramoto Tatsuo: Hey, today's my birthday, and my mom is throwing a party for me. It's probably just a really nice dinner, though. Anyway, do you wanna come by and hang out? Sasaki-San from our class might be coming, too. 

"Today is Soramoto-Kun's birthday.? Yakumo murmured to herself as she checked the date on her phone. "October 29, I'll remember that. But what should I do? I still have to hang the laundry. And I'm not done with my homework yet. But this is the first time Soramoto-Kun has texted me. Maybe I should go… It might help him open up to other people at school, too. But he said he invited Sasaki-San, as well. Maybe he's already starting to open up. It could help him open up even more if I go, right?" 

"Hey~~~! Yakumo~~~!" A female voice shouted from somewhere in the house, interrupting Yakumo's thoughts. "Can you come here for a sec~~~?" 

"Hmm? I wonder what Nee-San wants." Yakumo murmured to herself as she stood up from her desk with her smartphone in her hand. 

Wearing a contemplative expression, Yakumo walked through the house, eventually arriving in the living room where her sister, Tsukamoto Tenma, a short, about 5' tall, teenage girl with dark blue eyes, long black hair, and a slim, flat-chested figure, was excitedly bouncing in front of the television while watching a period drama called, "Three for the Kill." 

"Nee-San, did you need something?" Yakumo asked in a gentle tone. 

"Oh, Yakumo, can you---" Tenma replied energetically as she quickly turned around. 

While she was watching television, Tenma's most characteristic feature, the small pig tails she ties off from the rest of her hair, that flows down her back to her waist, were waving up and down energetically. And when she heard Yakumo's voice, they started waving even faster. However, as soon as she saw the expression on Yakumo's face, they drooped down as she put on a worried expression. 

"Yakumo, what's wrong?" Tenma asked, completely foregoing her original question as she rushed in front of Yakumo and placed a hand on her younger sister's forehead. "Are you not feeling well?" 

If anyone were there to see this scene, they would most likely say it was both heartwarming and hilarious. And the reason was that Tenma was shorter than Yakumo, who stood at 5'5" tall. 

"No, I'm fine." Yakumo replied while shaking her head gently. "I'm not sick or anything." 

"Then why do you look like that?" Tenma asked as she removed her hand from her sister's head. 

Instead of responding immediately, Yakumo considered her options. However, Tenma would not let her remain silent for long. 

"Come on, Yakumo, you can tell me." Tenma said as she grabbed Yakumo's free hand. "We're sisters. And you know I'll help you if I can." 

Despite the fact that Tenma was not someone you would be able to call intelligent or mature, when dealing with er younger sister, Tenma showed quite surprising levels of maturity… sometimes. 

"Well… The thing is…" Yakumo said, caving under her sister's caring behavior. 

Then, Yakumo told Tenma about Tatsuo's invitation and her apprehension because of all the chores she had left to do. 

"So, you're telling me this boy who invited you just transferred into your class a couple months ago?" Tenma asked. "And he has been having problems with connecting with other people?" 

"Yes." Yakumo replied with a nod. 

"and you think this might help him open up to other people?" Tenma asked with a smile. 

"That's right." Yakumo replied, nodding once again. 

"Then you should go." Tenma said with a gentle smile. "I know how much you like to help people, Yakumo. So, just do it." 

"But what about the laundry and the chores?" Yakumo asked. 

"Don't worry about those." Tenma said while thumping her fist on her chest. "I'll take care of all the chores. You just go and have fun." 

Instead of being happy that her sister would help with the chores, Yakumo wore a concerned expression. Seeing that, Tenma grabbed Yakumo by the shoulders and spun her around. 

"Seriously, Yakumo." Tenma said energetically. While pushing Yakumo out of the living room. "Just leave it to me. Now, you need to get ready to go." 

"Okay, if you say so." Yakumo said while allowing herself to be pushed out of the living room. "Then, I'll go get ready. And anything you don't get to today, I'll take care of tomorrow." 

"I already said, just leave it to me, Geez~~." Tenma replied after finally getting Yakumo out of the living room. "Just go on and have fun, okay~." 

Like that, Yakumo returned to her room to change into something she would not mind going out in. On the way back to her room, she thought she heard Tenma saying something about how her little sister's spring time was coming and that she needed to tell Mikoto-Chan. But she decided to chalk it up to her imagination. 

At the same time, Tatsuo had just stepped out of the elevator and entered his apartment. 

"Mom! I'm home!" Tatsuo shouted, announcing his return. 

As soon as the words left his mouth, Tatsuo heard the sound of footsteps fast approaching. Then, before he could even react, he was hugged tightly. Looking down, he could see a head of purple hair styled into a bun rubbing against his chest. 

"Oh, Tatsu-Chan, Mommy is so proud of you." Sumire said happily. "You're finally inviting some friends over. You even said two of them are girls. I knew my Tatsu-Chan would be the most handsome and popular boy in school." 

"Mom, please… Stop." Tatsuo replied in an embarrassed tone. "They're just friends. In fact, I'm pretty sure one of the girls is into the guy that's coming over." 

Hearing that, Sumire finally pulled away from Tatsuo. Though, she did not stop hugging him. 

"Really?" Sumire asked in a surprised tone. "Well then, you can't go after her, okay? NTR is bad." 

"*Sigh* Like I said, just friends, Mom." Tatsuo said while shaking his head. 

"Sure, sure, just come in." Sumire said, deciding she had heard enough. "You should go to your room until the guests arrive. We wouldn't want you to see the surprise, right?" 

"Whatever you say, Mom." Tatsuo replied with a shrug. 

With that, Tatsuo went towards his room. But when he arrived, he was surprised to see Mai standing in front of his bedroom door. And from what he could tell, she was crying. 

"Mai-Nee, are you okay?" Tatsuo asked in a concerned tone. 

Hearing Tatsuo's voice, Mai turned in his direction. And just as he thought, she was crying. 

"*Sniff* *Sniff* Tatsu-Kun, why?" Mai asked in a pitiful tone. "Aren't I good to you?" 

"Huh?" Tatsuo exclaimed in confusion. "Mai-Nee, what are you talking about?" 

"You're bringing another woman into this house. *Sniff*" Mai said, answering Tatsuo's question. "Isn't Nee-Chan enough for you? *Sniff* Have you gotten bored with Nee-Chan already? *Sniff* But what about the promise we made? *Sniff* That we would be together forever. Wah~~~~!" 

Reaching that point, Mai began crying loudly as she collapsed to her knees. Meanwhile, Tatsuo could only stare at her with a blank expression on his face. After hearing Mai's words, he finally understood why she was crying… sort of. Apparently, his mother must have told him about the guests he invited over. 

So, after figuring out what was going on, while maintaining his expression, he took a step forward, bent down to pick up Mai, took another step forward, and put her back down to the side of his door. After that, he opened his door and walked in before closing and locking it. 

"Tatsu-Kun~~~~! Why~~~? Wah~~~~!" Mai cried loudly. 

Attracted by the noise, Kasumi eventually opened her own bedroom door. And when she saw Mai sitting on the floor and waling at the top of her lungs, she simply shook her head before retreating back into her room. 

Meanwhile, in Tatsuo's bedroom, he decided at he would start creating his defensive gear for the mission. Though, he felt like it would become obsolete pretty quickly. Especially since there were better materials in the world of Infinite Competitive Dungeon Society. Still, it would be good to have some actual defensive gear rather than going in in just a track suit. 

Tatsuo spent the next hour working on his gear. However, he was forced to stop when he received a text alert. When he checked his smartphone, he saw a message from Yakumo. 

Tsukamoto Yakumo: I'd be happy to spend time with you on your birthday, Soramoto-Kun. 

Smiling at the response, Tatsuo replied quickly. 

Soramoto Tatsuo: Great. I'll send you my address. 

With that, Tatsuo sent the address to his apartment building and the number to use on the intercom in the lobby. Then, he decided to stop working on his gear for the time being. Instead, he left his walk-in closet, where his crafting tools were stored, and sat down at his piano. 

At that moment, he received another message from Yakumo. 

Tsukamoto Yakumo: Okay, I think I know where that is. I should be there in about half an hour. 

After reading the message, Tatsuo put his phone down. He had already told Chiho how to get up to his apartment, so he did not need to worry about her and Sadao. So, he flipped the key lid before stopping to think about what he wanted to play. A few moments later, Tatsuo lay his fingers on the keys. 

At the same time, the elevator doors opened to reveal Sadao and Chiho, both wearing casual clothes while Chiho's hair was let down, who had just arrived at the penthouse. 

"Good afternoon, you two must be Tatsuo's friends, Maou-San and Sasaki-San, correct?" Kasumi asked, greeting the guests as they got off the elevator. "It's nice to meet you, I'm Tatsuo-Kun's sister, Tenshin Kasumi." 

Hearing Kasumi's name, both Sadao and Chiho wore confused expressions. She had a different surname than Tatsuo, after all. 

"Oh, I was adopted, so that's why my surname is different." Kasumi said after noticing the two's confusion. 

"Oh, sorry about that." Chiho said awkwardly. 

"There's no need to apologize." Kasumi said while smiling gently. "Anyway, Tatsuo is in his room. Come with me, I'll show you the way." 

"Thank you for having us." Sadao and Chiho replied in unison as they took their shoes off. Then, they followed Kasumi inside. 

{BGM: "Like I'm Gonna Lose You" – Meghan Trainor feat. John Legend} 

On their way to Tatsuo's bedroom, they all heard the faint sound of a piano. 

"Wow! That sounds really nice." Chiho said as she narrowed her eyes. "What song is that?" 

"It's probably something that Tatsuo-Kun came up with." Kasumi replied, seeming used to the sound of the piano echoing through the apartment. 

"Huh? Does Soramoto-San play the piano?" Sadao asked curiously. 

"Yes, he does." Kasumi replied. "He's quite the accomplished pianist, too. Though, he's never participated in any competitions." 

Hearing that, Sadao and Chiho were amazed. And as they got closer to Tatsuo's room, they thought they could hear the sound of someone singing, as well. But it was too faint to tell clearly. A moment later, however, they could hear a male voice singing along with the music. 

"No~~, we're not promised tomorrow~. So, I'm gonna love~~~ you, like I'm gonna lose~~~ you. I'm gonna hold~~ you, like I'm sayin' goodbye~~~~. Wherever were standin'~~~. I won't take you for granted~~~~. 'Cause we'll never know~~~ when, when we'll run out of time~~~~." 

Hearing that voice, both Sadao and Chiho were amazed. Even Kasumi, despite having heard Tatsuo sing on more than a few occasions, stopped and closed her eyes gently to just listen. However, she was pulled out of her peaceful moment rather quickly when she realized why the volume of the music rose so suddenly. 

Looking towards Tatsuo's bedroom door, just as she expected, Sumire had cracked the door open and was recording with her smartphone. Meanwhile, Mai was looking into the room excitedly. 

"Um, what are they doing." Chiho asked in a confused tone. 

"*Sigh* Sumire-Sama likes to record Tatsuo-Kun whenever he sings or plays the piano." Kasumi replied exasperatedly. "And for some reason, she likes to do it in secret." 

"I… see." Chiho said, still sounding confused. 

"Either way, allow me to introduce you." Kasumi said as she started walking again. "The one with purple hair is---" 

"Shh~~~~!" Sumire interrupted. "Not while Tatsu-Chan is playing." 

As she shushed Kasumi, Sumire glared at the group of three sharply. The sharpness of that glare was so great that even Sadao, who had literally dealt with a nation of demons, flinched under its intensity. 

'She calls him Tatsu-Chan, that's really cute.' Chiho thought to herself. 'I wonder if he would let me call him that, too.' 

Like that, the group of five remained silent until Tatsuo finished his song.