Prologue:
Inside of Sturdytale hospital a doctor looks to a patient laying on a bed.
"We won't be able to save his body. But we can use his soul to save another patients life. It is a risky procedure and he is unable to give consent. So we need it from you two. His only living family members." The doctor looks upon two older teens who turn to look at each other. He has already gotten the permission of the other patients family. "In a way he'll be living alongside the monster his soul will help save."
"If he was in our position he probably would have said yes." The younger who is taller admits glancing away sadly.
The older who is shorter places a hand on the others arm. "I'm sure that he would have been thrilled at the idea that he is still able to help someone." He tries to offer up a small smile not feeling like he can smile more than that. "Dad did always like making inventions to help monster kind. So yeah he probably would have agreed to this."
The two turn back to the doctor who is patiently waiting.
"You have our consent." The younger informs the doctor who nods.
"Thank you. This patient will be so grateful for this." With that the doctor heads off to gather nurses to begin the procedure.
The siblings lean against each other to cuddle each other comfortingly. They turn as the other patient is brought in.
The patient is a huge white dog monster with a powerful looking muzzle. He has a tail with fur that wraps around it, his body fur being soft and fluffy looking yet not long. He is laying on his side eyes closed.
As the two watch the doctor uses a hint of magic to get the two to summon their souls. They can't help but notice that the dogs soul has cracks that are heavier on one side.
The doctor snaps the two souls in half gaining whimpers from the two. He finds that the part of the dogs soul most affected by cracks crumbles. He keeps pouring magic into one half of each soul he took that hes going to use. He brings them together until there's a light that shines.
Between the souls the light puts them together and goes down as though sealing that bond.
Once the light is gone the doctor puts the soul into place for the dog monster. He steps away and the soul fades into the monster's body.
The soul parts that are left over turn to dust along with the body of the siblings father.
"Goodbye Gaster." The older siblings mumbles softly.
After a few moments the monsters eyes snap open as he gasps. He sits up and glances around realizing he's in the hospital.
"Settle down." The doctor tries to soothe the dog monster. "We don't want you to put too much pressure on your soul right away." He is relieved when the monster nods then lays down. "Their father has given half of his soul to save you." He gestures to the brothers in which the dog monster turns to them.
In the dog monsters eyes is gratefulness after hearing this. "Thank you." He glances up as though alert to something that can't be seen. His smile widens a little. "He is here with me." He turns back to the brothers. "He wants me to tell you that he's proud of you both. And is glad that you made the right choice."
Hearing those words the brothers smile happy to know this. Knowing that they indeed made the right choice.
"As he's a part of me now, which I'm fine with, you two have joined my family."
"Thank you." The brothers nod to this.