[How] Can I make a wolf-like 'Guard' entity?

I want to make it so that an NPC can be tamed, and when tamed, they will follow the player but can be right clicked to made stay still. I want to make it so that if the player attacks something, or is attacked by something, even if another player, then like a wolf, the Entity will attack the player's attacker if near enough. How do I do this??  

EDIT: I would use the wolf preset, but I don't want it to sound like a wolf or be tamed with bones, and I want it to shoot instead of hit.