Nobody's POV:
"This is for Serena-chan!!!" Mitsuri said as she managed to chop Muzan's arm off but, he quickly regenerate so fast. "He's regenerating too fast! We need to slow him down!" Shinobu said as she was dodging Muzan's attacks. Then the fortress begin to shake as it was falling down.

"Guys!!! The fortress is going to break down!!! You all need to get outside before you get crushed in there!!!" Yushiro said as all of the demon slayers nodded to him until the floor broke apart as they fell through. "Incoming, guys!!!" Tengen said as they all saw the bottom of the floor even, they were somehow teleported outside too.

"We're outside! We need to hold Muzan off until the sun rise comes!" Muichiro said as Muzan was glaring at them in anger. "You'll all try to hold me off until Sun comes?! Then I'll kill you before the Sun rises!" Muzan said as they all fight him again. Meanwhile with Tamayo & Yushiro were hiding in a house for protection and shelter even, the battle is closer to the house too.

"Lady Tamayo! Don't go outside! I can't let you go into a middle of the battle!" Yushiro said as he was next to her. "I thought... I can get my revenge on... but, this took someone's life away. I never seen the Hashiras in hatred before... they love Serena so much but... now she's gone" Tamayo said as she was about to sit on the floor until she had someone behind her.

"Tamayo... please, don't blaming yourself. I hate it, when someone is blaming their self of my death" someone said as Tamayo widen her eyes even, quickly turns around until she & Yushiro see, who it was. It was Serena even, she looks really different too.

"S-Serena..?" Tamayo asked as Yushiro was shocked of this. "All of you... you, guys work so hard to defeat Muzan so everyone finally live peace" Serena said as she looked at the battle even, she is seeing they were not giving up too.

"This is, where I come in..." Serena said as she was about to disappear until Tamayo stopped at her at her tracks. "Serena! Why?! Why did you, let Muzan absorb you?!" Tamayo asked as tears fall from her eyes. Then Serena gave her one last smile at Tamayo even, answering her question.

"To destroy him from the inside.." Serena said as she finally disappeared. Both of Tamayo & Yushiro were shocked of this. Back at the battle as the Hashiras were trying to hold him off still until Muzan sent his attack at Tanjiro. "TANJIRO!!! GET OUT OF THE WAY!!!" Mitsuri said in fear for Tanjiro's safety. All of the Hashiras were terrified as Tanjiro was about to get killed until something happened. Muzan's arm became crystal as Tanjiro didn't get killed, he & the others were shocked to witness this. Then Muzan's arm got destroyed as he was in pure shock of this.

"What?! What's happening?!" Muzan asked in shocked as he tried to regenerate fast but, he can't regenerate fast because something is stopping him. Tanjiro was still staring at Muzan's arm got destroyed until he recognise the crystal. "T-That's... silver crystal" Tanjiro asked until he remembered, Serena explain to him about the silver crystal.

/Flashback/
Serena pulled out the silver crystal in front of him. Tanjiro's eyes were widen in amazement of the silver crystal.

"Tanjiro... do you remember, I cured Master Kagaya?" Serena asked him as Tanjiro nodded at her. "Y-Yes, Serena. Why?" Tanjiro asked as he was really confused of her.

"The silver crystal could do more than cure people, Tsnjiro. My mother sacrifice to save me and my friends from the evil forces even, our memories are a erase" Serena said as she was still looking at the silver crystal. "Also, the silver crystal can destroy us & the evil forces too. My mother did this to protect me and my friends from evil forces..." Serena said as Tanjiro had tears in his eyes.

"I didn't know... you went through this even, your friends got involved because your kingdom was destroyed by evil forces..." Tanjiro said to himself as feel so sorry for Serena. "Tanjiro, It's not your fault. This happens in circumstances even... my soul is connected to the silver crystal too" Serena said as Tanjiro's eyes were widen in shocked of, what he heard.

"W-What?! Your soul is connected to the silver crystal?! Why?!" Tanjiro asked as Serena looked back at him. "It's because it's my responsibility to keep the silver crystal safe from the evil forces. So, the silver crystal is connected to my soul. Even, I can still control the silver crystal too" Serena said to him as Tanjiro was amazed of this. Serena then put the silver crystal away to make sure it was safe.
/Flashback ended/

Tears fall from Tanjiro's eyes as he holds his sword tightly until he broke the silence.

"It's Serena!!! She's holding Muzan off!! Even, she's weakening him too!!!" Tanjiro said as all of the Hashiras were shocked to hear this. "What?! How?!!" Sanemi asked in confusion as all of them were still fight Muzan.

"When Serena got absorb by him! I think, she wanted him to absorb her!" Tanjiro said as he was dodging Muzan's attack. "But, how still?!! How is Serena do it?!!!" Tengen asked as he was looking at Tanjiro.

"Serena's soul is in her silver crystal!!! So, she's still alive!!! She's going to destroy Muzan from the inside meaning, the silver crystal will be destroyed too!!!" Tanjiro said to him. Muzan was shocked of this, he didn't see this coming. He didn't know, Serena plan this from the beginning. Muzan was going to die by them.