You are Gaster's child. Whether human or not, that is your choice. He had created you in a lab years ago, and you are now 7 years old. He allows you to roam the Underground as you please. Yet, he always tells you to avoid the Ruins. However, your curiosity got the best of you, and you decided to go whilst he was working. You had eneded up breaking a bone. Now, he is sitting with you, trying to heal your bone whilst you squirm because it hurts.
"My child, you must calm down. You are only making things worse for yourself." He said, his tone calm and mellow, his voice the same as it always is despite his worry for your safety. You have not told him why you got hurt. Are you willing to lie to him? He can read you well. It might be a bad idea. But, can you even tell him you went to the ruins? Would he get mad? You aren't sure.