The swordsmiths would rebuild their village and move it some place else, that way the Demons won't find them. 

You and Tanjiro bid goodbye on good terms with the swordsmiths with Haganezuka giving Tanjiro his newly made sword! 

You also gave Kotetsu words of encouragement, knowing he would become a fine swordsmith. 

Muichiro was healed up very nicely too. The young Hashira was much happier than before. 

Also, Tanjiro had Nezuko's new blood transferred over to his ally, a demon doctor named Tamayo. 

Meanwhile... 

Tamayo and Yushiro (Two Demons who are allies of Tanjiro and Nezuko! Tamayo was a doctor who was turned into a demon by Muzan, and helps however she can to combat him! Yushiro was a human who Tamayo saved, when he was dying of a terminal illness! As such he has gained a massive crush on her! He really doesn't like it when people get close to her!) 

Tamayo wrote a letter to Tanjiro. 

Tamayo: "Tanjiro, thank you for supplying both Nezuko and the Kizuki Blood of the Lower and Upper Moons. One of Muzan's victims got his consciousness back. And thanks to Nezuko's blood now he can live free of his unluence with just a small amount of blood. I think inside of Nezuko, there's something more important than becoming human again right now. But that's just my speculation." Yushiro! 

Yushiro: Yes, Lady Tamayo? 

Tamayo: Bring Chachamaru here. 

Yushiro: Right away. 

Meanwhile... 

Akaza had heard the news of what happened. 

Akaza: (Y/N) (L/N), you never cease to amaze me. But, mark my words- 

He crushed a rock. 

Akaza: I will make you a demon, so we can fight forever! 

At the Butterfly Mansion... 

Team RWBY:  WHAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAT?! 

Aoi: Do you have to be so loud? 

Aoi rubbed her ears which were in pain. 

Sumi, Kiyo, and Naho: NEZUKO IS TALKING?! 

Blake: And she's in the sunlight? 

Nezuko: Welcome back everyone! 

Ruby and Weiss: SO ADORABLE! 

They hugged her. 

And then-

???: OH MY GOD! SHE'S SO FUCKING CUTE! 

Zenitsu appeared. 

Aoi: Oh no. Just what we needed. This parasite. 

Zenitsu: NEZUKO!!! 

But as he ran to her, Yang uppercutted him. 

Yang: GET LOST ZENITSU! 

Zenitsu: WHY ME?! 

He then got back up. 

Zenitsu: NEZUKO! YOU'RE SUCH A BEAUTIFUL THING! IF WE GET MARRIED I'LL FEED YOU EEL AND SUSHI EVERY DAY! SO PLEASE MARRY ME! 

Nezuko: Thank you for the offer, Zenitsu! But- 

Zenitsu: B-But? 

Nezuko: I love (Y/N)! 

Zenitsu had an angered look on his face. 

Zenitsu: BASTARD!!!! 

Weiss: Wow, that was cold, and coming from such a pure thing. 

Ruby: I wonder how Inosuke would take this? 

Blake: Well, I can see him going- (Inosuke impression) HAHAHAHAHAHAHAHA! YES, MY LOYAL MINION! TELL OFF YOUR JUNIOR LIKE THAT! 

Yang: HA! That's just like him! 

(Y/N): What's u-

 Team RWBY: (Y/N)! 

(Y/N): Oh sh- 

They all tackle hugged and kissed you! 

(Y/N): Great to see you're back. So how were the missions? 

Yang: We kicked ass as usual! 

Ruby: And developing our Breathing Styles! 

Weiss: Hmph. Well, I invented a new style. You could say I'm already ready to become a Hashira! 

(Y/N): That's great Weiss! 

Yang: Ha! In your dreams Ice Queen! 

Weiss: And why not? Muichiro is younger than us and he's a Hashira! Shinobu is also younger than us! Hell, we're older than Mitsuri! 

(Y/N): Easy there. I'm sure things will work out fine. Say, I wonder how the Hashira are. 

At the Ubuyashiki Mansion... 

Sanemi: You guys fought Upper Moons?! YOU SHITTING ME?! WHY DIDN'T I RUN INTO ONE?! 

Obanai: It's not like people bump into them all the time. But how are you, Kanroji, and Tokito? 

Mitsuri: I feel just great! (Y/N) took me out for some sakura oni giri the other day! 

Obanai: (jealous) Oh ... that's- Just- 

He got stressed out. 

Obanai: WONDERFUL! 

Muichiro: I'm not at my full strength yet. 

Gyomei: It was a close one! It's so sad how we've lost so many Hashira in the past! But defeating two of the Upper Moons is wonderful! 

Shinobu: I'm happy to see that you all recovered quickly from those endeavors. 

Giyu: Master probably wants to discuss these matters too. 

???: Actually- 

Amane, Kagaya's wife appeared. 

Amane Ubuyashiki (Kagaya's Wife!) 

Amane: I will be taking my husband's place. You see ... his disease is getting worse. ANd he sends his apologies for being unable to attend. 

Gyomei: M-MASTER! 

Gyomei began to cry. 

Gyomei: I will pray for his recovery. Please stay strong, Lady Amane. 

Amane: Thank you Gyomei. As a result, he gives this to all of the Hashira. Muzan is aware of Nezuko having conquered the sun. And now he seeks to devour her. It's time to prepare for the final battle. I ask that you train hard. It seems that marks have appeared on Demon Slayers during the Sengoku Period. These marks have increased everyone's skills. (Y/N) informed us about Tanjiro's mark, as well as Muichiro and Mitsuri having one. 

Mitsuri: HEY! I think I get it! Yeah, my body was going all crazy just feeling it! 

Muichiro: Yes, I know. I felt that too. It happened when my memories came back. My body temperature increased as well. 

Amane: In that case, everyone be ready to train for our final battle. 

Giyu: Of course. I will take my leave Lady Amane. 

Giyu began to leave. 

Sanemi: HEY WAIT! Where are you going Tomioka?! We still have to- 

Gyu: I have my own business to go too. 

Sanemi: WHAT DO YOU MEAN!? 

Shinobu: Mr. Tomioka, what's wrong? 

Giyu: I'm ... not like you guys. 

Sanemi: WHAT?! WHAT THE HELL DO YOU MEAN BY THAT?! ARE YOU MOCKING ME?! ARE YOU MOCKING ALL OF US?! ARE YOU MOCKING RENGOKU TOO?! 

Mitsuri: Shinazugawa, please don't! 

Gyomei calmed Sanemi down. 

Gyomei: Please. I have a proposition. 

Back at the Butterfly Mansion... 

Inosuke: AAAAAAAAAAAAAAAAAAAAARGH! 

Genya: WHAT IN THE?! 

(Y/N): HUH?! 

Inosuke burst through the window! 

Inosuke: TRAINING TIME! 

Ruby: Inosuke? Right n- 

Inosuke: YES RIGHT NOW IDIOTS!! 

Weiss: DO YOU EVER SLEEP?! 

Inosuke: NO! HAHAHAHAHAHAHAHAHAHAHAHA! 

Weiss: How brain-dead are you? 

(Y/N): What kind of training? 

Inosuke: HASHIRA TRAINING! 

(Y/N): Huh? 

It turns out all of the Hashira will be training everyone! 

Soon enough... 

The Hashira training was plain simple. Uzui would be doing stamina training, Mitsuri will be handling flexibility, Muichiro would deal with quick movements, Obanai would focus on Sword Skill Revision, Sanemi would handle infinite pounding (resistance), and Gyomei would handle muscle reinforcement. 

But Giyu didn't participate. 

(Y/N): GIYU! HEY! GIYU! 

Tanjiro: MR. GIYU! 

You both went to check up on him. 

(Y/N): Are you going to participate? 

Giyu: No. 

Tanjiro: Why not? You seem ... disappointed. 

Giyu: Someone has to be the Water Hashira right now, because it's vacant. 

(Y/N) and Tanjiro: VACANT?! 

(Y/N): But you're the Water Hashira. 

Giyu: I'm not. 

He then got up and left. 

(Y/N): WAIT! WHAT DO YOU MEAN BY- 

He was gone. 

Tanjiro: What's gotten into him? 

(Y/N): I say we ask. 

You both begin to follow Giyu around, but he kept trying to leave. 

Four days later... 

Giyu: I never passed the Final Selection. 

(Y/N): Wait, you mean the one where you become a Demon Slayer? 

Giyu: Yes. There was a boy who was killed by demons. His name was Sabito. Back then I was 13 years old. He was my friend, and we both lost our families of the same age. He had a strong sense of justice, and was kind-hearted. He died in the Selection that year. I was injured by a demon who attacked me in the beginning, and Sabito saved my life. When I came to after losing consciousness, I was selected for surviving 7 days. But- 

He seemed sad. 

Giyu: I'm a human who couldn't beat a single demon, and I was bailed out. Did I really pass? I'm not worthy of being a Hashira. I'm not worthy of standing with the others as equals. I'm nothing like them. I shouldn't have come here. 

He then started to leave. 

Tanjiro: Mr. Giyu. 

(Y/N): Giyu, you- 

Giyu: Just leave me alone. 

You both thought of Rengoku, and how he put his life on the line for all of you, and died doing so. 

(Y/N): GIYU! SABITO DIED FOR YOU, YOU KNOW! IF YOU'RE NOT A HASHIRA, THEN YOU'RE FORGETTING ABOUT WHAT HE GAVE TO YOU! 

He then remembered- 

Sabito's Words: Don't your ever say that you're nothing ever again! If you do, I won't be your friend again! Your sister was supposed to get married the next day, and despite knowing that, she hid you from the demons and protected you! You have nobody else?! THAT'S AN INSULT! You can't die either! That life she lost to protect you?! It's your future! 

(Y/N): He's still inside of you. So don't ever think about calling yourself nothing like the others! You deserve your title! Whether you think it or not! 

Giyu: Why did I forget about that. I didn't want to remember it. I kept on crying and crying. Whenever I did remember, I got sad and didn't do anything. Tsutako, Sabito, sorry for my immaturity. 

He seemed to be sulking. 

Tanjiro: (Y/N), I think Mr. Giyu is- 

(Y/N): Uh ... hello? Giyu, are you- 

Giyu: (Y/N), Tanjiro. I'm sorry. I'll go and train as w- 

(Y/N): Not on an empty stomach! Tell me, what's your favorite food? 

Giyu: Soba. 

(Y/N): Alright! We eat and then we train! 

Giyu: (confused) W-Why?