Malcolm and Pewdiepie are in fact brothers.
It all starts in late 2002 when pewdie's father went out on a night out drinking with his friends he was walking home a little the worse for wear when he stumbled across an old abandoned building, he was dared by the group of friends he was with to spend the night in there to which being shit faced he readily agreed to. what happened that night is only known to the authoritys and pewdie's father until now. he was set upon by an escaped female mental patient and forced to do... well i think you know what. he made a report to the police and she was captured and returned to the asylum 9 months later malcom was born he was sent away for adoption as pewdie's father didnt want reminding of what had happened that night. years later malcom discovered the truth after he found his adoption papers, this is when he decided to start doing what all little brothers are best at and being a little shit. although pewdie is unaware of this on a conscious level he may be aware on a subconcious level as he verbaly holds malcom down and farts on his head.