Papyrus had watched the exchange of the picture that his new friend, Mercy, had made for his brother. Like he thought he would his brother did like it. How ever he did not expect his older brother to react in that way. Not at all. He can't recall the last time he looked so awed at at a gift and that is including gifts he had given him in the past for giftmas's and birthdays. He felt a warmth in his soul seeing this and relief that some of his brother's feelings are not all lock behind his mask of fake cheerfulness that he constantly wears.

He out of habit checks his brother's hp level like he normally does every ten minutes when they are around each other and feels his eye sockets bug out at what he saw as he turned jaw dropped reaching out a bit towards him. His brother's hp max hp was growing. He hears him say he will be back for lunch and teleported away before he could ask him to stop. His arms went back down to his side as he tried to process what he just witnessed.

His brother used to have a high hp. Around 750 hp when his brother was a teen and he a youngling. He does not know the exact cause for his brother's hp to drop verses going higher like most monsters do until they reach their maximum when they turn middle age but it had before tapering and lowers slowly off when the monsters become old, depending on the monster type it takes a while to reach that point.

He remembers being told when he asked someone when he was older about his brother's hp ever having the chance to ever go up again and go to the level it was suppose to be. Needless to say he was disheartened when he was told that his brother would never have that chance because once a monster looses their hope and it dwindles it means that there is no way for a monster, in normal means, to get it back. The best he could do is to try and make his brother comfortable and keep his one remaining hope from going so he will not fall down, which is a higher risk since he has just one left. Or rather, had one left.

… His brother's hp grew. It grew. It grew! "IT GREW! IT GREW! OH MY DEATA RUNE AND ALL THAT IS HOLY STARS HIS HP GREW!" he cried out as tears of joy flow freely as he lets out a cheer of joy grabbing a hold of Mercy, since she was the closest person at the moment, and hugged her spinning. He let out a happy laugh before he sank slowly to his knees crying harder as he felt all the fears and worry that he held in his soul melt away.

"I-I'm so glad... so glad..." he said his voice sounding so soft. He can't remember the last time his spoke this softly. He felt a pat on his shoulder and looked to see Mercy giving him a confused look as she tried to comfort him. "I'm... glad his hp had grown but I do not quite.. understand why it is something that.. well.." He hears her say. Oh. Right. She did not know since she just got here and as a human is likely not able outside of an encounter able to see a monsters max hp.

"OH. SORRY MERCY. ALLOW ME TO EXPLAIN. SANS HAS A LOW HP, ONCE HIS HP WAS VERY HIGH BUT ONE DAY IT INEXPLAINABLY DROPPED DOWN TO ONE. I WAS TOLD THAT THERE WAS NO CHANCE FOR IT TO EVER GROW AGAIN AND WHEN HIS HP GREW FROM... from one to five... I do not know how but... it made me feel so happy." he said with a sniff as he rubbed his skull with his hands te dry the tears after releasing her.

"Oh... oh. I think I might know.. not sure one hundred percent but I may have accidentally effected his soul with with mine... it is kinda different than most souls and I have no clue for sure what my soul is able to do but it according to Toriel has the potential to use magic and I have it radiating off me. I think when he was reacting positively to my gift it allowed his soul to be able to soak up the excess that my soul had leaked out unknowingly. And that is just my guess at a partly explainable answer cause I have no clue what so ever by what my soul looks like what it's trait is one hundred percent. Sans said that he would help me figure it out late but..." She says to him playing with the hem of her sweater, which he noticed has the Delta Rune symbol that is usually worn by the king and the royal guard.

Is this Toriel royalty and gave it to her? He recalls in the text books in school that King Asgore had a wife and her name was Toriel... he will have to file this away to ask later because the rest of her explanation suddenly struck him hard in his soul as he looked at her his eyes bugging out. He did notice that there was a odd magic in the air. He thought nothing of it cause it was not really causing him any harm, so it would not harm his brother either. He figured it was just the magic from the core working through the cooking process cause the cooking of the spaghetti was going longer then it normally would.

….. Well. This solidifies his resolve. He is going to make Undyne accept Mercy as a friend and not be murdery of her. One way or another he will convince her to spare his new friend. Originally he was on the fence on how to do it but now... now he can not afford for his new friend to be harmed just for her soul. With how he had seen how her souls natural aura off put effected his brother when he allowed himself to open up even if it was just for a moment it became clear. She is special. And must not come to a untimely end. He knows deep in his soul and feels his core trait of bravery blaze strongly.

She is his brother's chance for becoming whole. And it fills him with hope.