Sans and Frisk body froze hearing a foot steps that keep getting closer to them.. then the figure appear with their cruel smirk...
a yellow cat.. he have twisted smile like he is mad...

"Well well well... look who is playing on my back....even you Frisk... even you...YOU BETRAY ME!!"
"I-its not like that i-"
"COME HERE!!"

he scream and Frisk slowly walk away from Sans to him, but then he grip her hands refuse to let go...

"Sans...please understand... I will be fine i promise.....don't worry"
"But he seems li-"
"Mad? Yes... but i know why... and im sure i can cure him... please Sans.. just this time.. let me go.."
"Just this time... but let me do something for you"

Sans hug her, and silently put a glowing soft blue stone in her pocket, then Sans let Frisk go to him who roughly yank her hand...

"I know you wana go away right.... you want to leave me suffer alone right!!"
"N-no bro..i-"
"SHUT UP!! And for you!! All of them call me Burger pants!! All of you think that's funny ?? I have MY OWN NAME!! BUT ALL OF YOU KEEP CALL ME THAT!! Now i must life under that name!!"

He keep babbling while giggling now and then, Sans really sure that he have unhealthy soul...and the fact that he grip Frisk arm so hard not help him calm his mind...

"Let's go home Frisk!! I won't allow you to live on your own again!! I will get MK after this!!"

With powerful yank....BP pull her away from Sans and she is gone with one last glance to Sans who try to hold himself all the time...
How can he see his beloved got hurt like that... but she beg to him to let her go..and Frisk never lie...she already promise him that she will be fine!!! But GODDAMN THIS IS MAKE HIM FURIOUS!!!

He felt his head spin... and he quickly went home... and collapse to his sofa with whimper... he must save his power for later...
The midnight comes, the moon is shine brightly on Frisk who sadly staring outside her window. She got locked by BP in her old room... but he miss Sans already...
BP put MK in different room from her and he not happy with this... MK hate him from beginning and the his hatred grow when he watch him beating Frisk up...
Frisk sigh... she miss Sans... she know it's not right... she only meet him...but...
Frisk sigh sadly and a single tears fall from her eyes...

"Sans... i miss you.... "
"Well...*huf...* if you *huff..* me that much.. *huf..* why don't u give me some help here.."

Frisk started by the voice that she know very well... and when she spin her body, her eyea widen when she saw Sans who collapse on the floor... he look really pale and very tired...
Frisk run to his side and hold his hand...

"Sans!! What happen?"
"Heh... don't worry sweetheart...i just.. running out...of magic... could you...give me a stone in your pocket..."

Frisk reach her pocket and grab the object... blue ston shine brightly on her hand but she don't have time to admire this object... Sans need this more than her...
Carefully she give the stone to Sans who place it on his chest and absorb it...

"Wha?!"
"What?"
"How... you...you absorb it?"
"Eh... originally it's half of my soul... so yea.. i can absorb it"

Then Frisk remember his state when he arrive

"So... you.. made me hold half of your soul..even if it's make you weak!!? Are you crazy!!"
"Yep..."
"I kno y-"
"Crazy for you"

Frisk blushing hard... and playfully punch Sans on his chest, Sans already look better in ft his point...

"So.. why do you come here?"
"Aww... is not you the one who tell me that you miss me a minute ago?"
"Wha- y-yes it's true..b-but.."
"Hahahha calm down.. yeah... i have my reason... "

He gently touch her head and put his forehead on her..

"I will protect you with my life"

Once he said that... the vision of someone who smile at her warmly and kiss her hand appear then he said the same thing that Sans tell her a second ago..

"I will protect you with my life"

Then all gone with blur, leaving her with a hug headache that made her clench her head hard.

"FRISK!!"
"Sans..."
"You ok sweetheart?!"
"Sans!!"

The tear fall from her eyes... he remember something... but not much..but she can sure that's Sans and her...not a strangers...
Sans keep starring at her with worries in his eyes.... and Frisk happy with it.. but.the moment must go because something knocking the doors....

Now all of you know who is that guy: 3