Just so everyone knows, that pup is his summon's reduced form. Well, more like a connection between him and his summon.
Pretty much it makes sure he has a way to summon his summon. Plus, he can say it is just a pet.
---------
And now... Just so you know, Edward's clan is not full of good people. They are closely linked with Duran's but they see them as a kind of trator, and might be why his mother is sick or dead. POISONED very sutblely by his clan.
Also, they usually kill their opponents. Just so you know.