Ace better known as Ace the Bat-Hound

Or Bat-hound like his nickname 

is Batman's patner dog.

(although he says sidekick)

and has a well-trained, obedient, fiercely loyal personality.
lives with his sidekick batman in gotham city and 
affiliated with the Dog Star patrol his friends 

as he does not like to be called Being called pet, foolishness

friend list

Krypto
Kevin Whitney
Streaky
Stretch-O-Mutt
among others

 He has a sense of humor and has a hard, cold stare.