Frisk curled up into her knees, leaning against the door of her bedroom, softly crying.
She had been through a lot, having traveled to the Underground as an orphan, then meeting several friends who had changed her life. One of them, Chara, was the closest. She had been a ghost for the longest time, having guided Frisk throughout the Underground. When the barrier was destroyed, Frisk stayed with Toriel in the realm, and was adopted.
Chara felt worried. "What's wrong?"
"M-My birth parents...I miss them..."
"Oh..." She kneeled, placing her see-through hands on Frisk's knees, head down, softly whispering. "I'm sorry... I'm so sorry..."
"Thanks, Chara..." Frisk faintly whispered in reply.
"You're welcome, Frisk..." With that, her friend's ghost body became solid for a while. She was pulled close. "It's alright...you're part of our family... You're my sister, now...the one I never had. And the war's over. We can finally live together in peace."
Frisk smiled for a little bit.
"Are you okay?"
"Yeah... I'm tired..."
The two of them pulled away, Frisk getting into bed. Chara faded to her ghost form again.
"G'night..."
"You too..."
Frisk fell asleep instantly, Chara watching over her.
At last, everything was peaceful in the Underground.