Your family is wealthy so they need protection from dangerous people..

your dad brought home a human in a cage he had muzzle, lots of brusises and scars covering his body he attacked his previous owners. Your dad wanted to train him and use him as a protection. But it was more difficult than he thought and it didnt worked, he was getting more pissed each day, he was hitting this "mad dog" one day your dad had enough he aimed his gun wanting to kill this guy in cage but you stopped him didnt want to see a human being be treated this way you told him, you'll try to train him

now youre in your room in front you is muzzled and chained up guy he doesnt even have a name so you dont know what to call him