Having hugged the Child long enough to dry up her eyes. Toriel guided Frisk to her home, led them to what seemed to be Chara's bedroom, and left them to run to the kitchen.
Frisk had time to explore the room before Chara comes back, so they sat on the bed. It was a child's room with different toys, a medium-sized closet, and two drawers. There was an empty photo frame on one of the drawers, Frisk wondered whose photo was there, but guessed it was some family shot Toriel took away. There was not much besides some clothes like the Child and drawing that seemed to be Chara's. Before they could look any further, they felt the Fallen in the room. Their face was both sad and displeased :
"Never pull that on me again, Frisk"
"I am sorry, she seemed so eager to see you."
"I know she is, and so I am but ... I am not ready to face Mother yet."
"Who wouldn't like to see their mom again?"
"Listen, it is something difficult to tell right now ... We can talk about it later. Please rest now, I have been hard on you this whole time and -"
"You should sleep too, so I will take this side of the bed" thus Frisk hugged the wall to let Chara hop in. They did not really expect them to come and sleep because they were ghosts but:
"Alright, I might get some actual sleep, but you'll have to hold my clothes. Don't try anything funny." said an unusually polite Chara, who thought it would be best not to argue again with their bedmate.
Frisk understood why would Chara warn them when they closely look at their bruised body, something budded out there that they had not. They blushed but held Chara's clothes while the Fallen settled up for sleep. Their arm went sore from keeping a hold on the fast-asleep Fallen. They changed arms to keep them "alive" so they can sleep, but that did not last long either. They thus quietly tried to hug Chara, who noticed the embrace but was too sleepy to rant at them.
They both slept all night long without much trouble, especially Chara who never thought they would ever enjoy a proper slumber again. Frisk woke up first, but did not move until Chara woke up :
"Good Morning!"
"Good Morning, you can now let go of me, thank you"
Frisk thought Chara's cold voice fitted them well, so they did not mind it anymore. He left them alone and found some pie on a plate with a note from Toriel :
"Hungry?"
"Hm? Oh yes, Mother's pies are my favorite in the Underground. Is it cinnamon-butterscotch?"
Frisk nodded once they had a bite, ate half of the pie, and passed it on to Chara who devoured it in an instant.
"When are we leaving? We can stay at Mother's so you rest properly but unless you want to live here, we will have to leave soon."
"I will talk to her tomorrow, and so will you. I cannot see why you would not see her off at least."
"I will let you know if I can tonight then, now Child ... we should go back to the Ruins and have you train some more."
The child obeyed, though weary from the previous night. Chara knew they were for the sake of their good night slumber but remained firmly determined to have the child keep themselves alive. As Frisk exited their temporary room, Toriel was up the stairs with a chocolate bar and some spare clothes.
"Good morning, little one. I see you liked my pie" while smiling at Frisk. They nodded and smiled too, picking up the chocolate bar before going out back to the Ruins. Toriel followed them silently to check on them but was relieved they were not having trouble fighting monsters peacefully. She went back, picked a book, and took pleasure in reading it while remembering Chara and her deceased son playing nearby. She wallowed a bit on it before giving her full attention to her snail spot book.
Frisk went back to the Ruins and practiced some on monsters, as they were slightly stronger now. Chara's few monster kills had made them a little more resilient too, but they were not one for fighting anyway. After eating some chocolate, and giving it up to a hungry Fallen who ate it with glee, Frisk found a room with no monsters, a painting of crystals, and a giant castle was the wall and they could not help but admire it. They noticed a knife on the ground, and shivered a bit since their killer was nearby, but took it nonetheless. 'Toy Knife' was on inscribed on the back of the handle.
"Hey Chara, I got one too now" while hiding well their fear from the Fallen's twisted alter ego. Chara looked distant, almost absentminded. They fixated on the painting on the wall much more than Frisk did, left their bangs covering their red eyes, and cried an eyeful while falling on their knees. Frisk dropped the knife and went from one more wary embrace. Their SOUL pulsated briefly, and what appeared in front of them was something they already saw twice.
"Hello Chara, it's me, your best friend!"
"I am not Chara, sorry, but they are right beside me, Who are you?"
"Oh, you - you look so much like them. Have they not talked to you about me?"
"They never mentioned their name, but you look like their Mother."
"Ah, I understand ... By the way, I'm Asriel! Nice to meet you, Chara's Friend"
"Hey Asriel, my name is Frisk, and you look ... nice !"