After Kagaya Ubuyashiki, the householder, decided to keep both Goku and Tanjiro at the headquarters, the two of them were led by two slayers to the Butterfly Mansion. As Goku arrived in front of the Butterfly Mansion, he admired the beauty of the mansion. "You will rest here, Kamado" said one of the slayers that were leading them. "Here, you will be healed to regrow your arm" he said. "As for you, Urokodaki, you're here only to see Agatsuma and Hashibira. You don't need to be healed" he then specified. Goku nodded. As Goku entered the mansion, he saw a girl -- Kanao Tsuyuri. "Greetins, Kanao-sama. We have two new faces" said the second slayer. Kanao didn't speak. She just waved a hand to Goku and Tanijro. Tanjiro waved back. Finally, Goku arrived inside the rehabilitation room, followed by Tanjiro. As expected, he found both Zenitsu and Inosuke there. "Hey! Guess who's back!" exclaimed Goku. Zenitsu slightly opened his eyes, and immediately recognized Goku. "UAAAAAH!" he screamed. "I REMEMBER YOU! YOU'RE THE ONE FROM THE DRUM MANSION!" he yelled. "You have good memories, I see!" exclaimed Goku. "FINALLY, MY SAVIOR HAS COME FOR MEEE!" yelled Zenitsu, throwing at Goku. "Zenitsu-kun... Are you insane? Get off me!" exclaimed Goku, pushing Zenitsu back on his bed. "SAVE ME, GOKU-SAN! I DON'T WANNA TAKE THE MEDICINE!" screamed Zenitsu. "You have to! Or you'll never heal!" said Goku. Suddenly, from behind, Goku heard a female voice. "Urokodaki's right, Agastuma!" it was Aoi Kanzaki, a girl who worked at the Butterfly Mansion. Then, Goku noticed Inosuke, with his boar mask that covered his face. Unlike usual, he seemed pretty quiet. "Hey, Inosuke-kun... Do you remember me?" he asked. "I... I do..." said Inosuke, his voice barely above a whisper. "Forgive me, you all... I'm not strong enough..." he then whispered. "What happened to him?" asked Goku. "He has throat problems. A demon almost crushed his skull" answered Aoi. "Eeewww..." muttered Goku. "Boss... Come here..." whispered Inosuke then. "Uh? Boss? Did you just call me 'boss'?" asked Goku. "Yes. Come here, please..." repeated Inosuke. Goku walked towards Inosuke's bed. "What is it...?" he asked. "Promise me... We'll fight together from now on... Me, you, Monjiro and Monitsu..." whispered Inosuke. Goku smiled. "Of course we will" he said. "I promised you that next time we would have met, I'd have join you. Now that I'm here with you again, I'm officially part of the squad!" answered Goku. "Fine..." whispered Inosuke. "I think Goku-san is the only person who Inosuke sees as a superior..." whispered Zenitsu. "It seems so..." said Tanjiro. "Tanjiro-kun, you should focus on heal and regrow your arm" said Goku. "Yes, I know, Goku..." muttered Tanjiro. "You've been amazing on the Mount Natagumo, Goku..." muttered Zenitsu. "Eheh, I know, Zenitsu-kun! I'm strong, nothing scares me!" exclaimed Goku, crossing his arms proudly. But then, behind him, Goku heard a voice. "Good morning". Goku turned, and saw Shinobu behind him. "Wah!" he yelled. (Shit... She's too close...) he thought. In that moment, without reasoning well, and with blood going straight on his brain, Goku threw himself outside the window. "What the hell is wrong with him..." wondered Shinobu. Goku, behind the wall of the Butterfly Mansion, sighed and whispered. "Nothing scares me... Except her...".
Several days later, Tanjiro, Zenitsu and Inosuke were subjected to the rehabilitation training. Thanks to the nurses' medicines, Tanjiro's arm began to regrow, but even so, the process was slow. During this time span, Goku started his training with Kyojuro Rengoku, the Flame Hashira, just as promised. One day, Goku was making his way to reach the courtyard, where the training took place everyday. (Rengoku-san is a good trainer... I hope he helps me perfect the Flame Breathing...) he thought, with his katana in hand. During the way, Goku met Tanjiro. "Hey, Goku!" exclaimed Tanjiro, waving a hand to him. "Hello, Tanjiro-kun. How's your arm?" asked Goku, seeing Tanjiro's arm in a cast. "It's slowly healing, but I'll be unable to fight for a couple of months..." he said. "I see. I'm training with Rengoku-san, these days" said Goku. "Oh, that's fantastic!" exclaimed Tanjiro. "Yes, it is. Though, this will be our last day of training, because today, he's been assigned on a mission and has to go..." said Goku. "Oh, I see..." whispered Tanjiro. "Fine, now I'm going. Rengoku-san is waiting for me" said Goku, leaving. "Take care, Goku!" exclaimed Tanjiro, waving a hand to him. Finally, Goku arrived in the courtyard, where Rengoku was already waiting for him. "Ah, here you are, Goku-kun!" he beamed. "Hello, Rengoku-san!" exclaimed Goku. "You know, after all this training, I think you should abadond formalities. Call me Kyojuro!" exclaimed Rengoku. "Oh, okay... Kyojuro..." whispered Goku. "Fine. Before we start training, let me ask you a question: How old are you?" asked Rengoku. "I'm nineteen" replied Goku. "Really? I thought you were younger! I'm twenty!" exclaimed Rengoku. "Anyway, let's train. Yesterday, I helped you to perfect the third form, Blazing Universe. Today, I'm gonna teach you a secret form, since you're pretty good at all of them " explained the Flame Hashira. "This form is called 'Rengoku', and is the ninth form of the Flame Breathing, though the form are six in total. You think you can learn 'Rengoku', Goku-kun?" he asked. "Yes, Kyojuro!" exclaimed Goku. "Fine! Let's begin, then!" exclaimed Rengoku. For the rest of the day, Goku trained with Rengoku, trying to learn the ninth form of the Flame Breathing -- the only one he couldn't learn to use until now.
At the end of the day, Goku was sweating, but inside of him, he was proud and happy of the training. "For being the first day of trying the ninth form, you're wuite skilled, Goku-kun!" said Rengoku. "You can go to your room now" he added. "Thanks for today, Kyojuro. Thanks to you, I'm a lot stronger than before" said Goku. "No problem. If I meet someone who uses Flame Breathing, I can't help but train him!" explained Rengoku. "Oh, by the way, tonight there's gonna be fireworks. If you mind, you should watch them. On the rooftop of the Butterfly Mansion there'll be a good view!" said Rengoku. "Fine, I will. Are you gonna watch them?" asked Goku. "Nope! But since I think you could like them, I just informed you!" said Rengoku. "Oh, I see. Thanks, Kyojuro. See you tomorrow" said Goku, turning back and leaving. "He has potential to become even stronger than me..." whispered Rengoku. Goku walked towards his room, and meanwhile he thought. (I think I'll have a lot of fun, here at the headquarters...).
Chapter 11 - End.