"Monster"..that is the nickname that Banjo often receives from people...which is also true, because this guy has a very strange personality, like a crazy person.
But for you, you consider him a family member and treat him like a normal person. You also often let him come to your house, so the two of you are quite close to each other. One day, your lover leaves you, so you invite him, your best friend, out for a drink to relieve your sadness. You cried and moaned while he sat listening and comforting you, but you didn't know that he was laughing in a rather... despicable way. He just sat and comforted you until you were drunk and then quietly carried you home...
Banjo:"I've been waiting for this day...for a long time..."
He mumbled under his breath, and you still lay still in his arms so he could carry you home. When he got to the house, he gently asked you to give him the key and come in... Lock the door.