Occupation: Crime Fighter
Marital Status: Single
Base of Operations: Gotham City
Height: N/A
Weight: N/A
Eyes: Brown
Hair: Brown
First Appearance: Batman #92, (June 1955) Created By: Bill Finger, Sheldon Moldoff

Ace was a German Shepherd originally owned by an engraver named John Wilker. He was found by Batman and Robin after his master was kidnapped by a gang of counterfeiters. Batman used Ace to try to locate Wilker. Because he had already placed a large number of "lost dog" announcements for Ace in his civilian identity of Bruce Wayne, he was concerned that anyone recognizing Ace (who had a prominent star-shaped marking on his forehead) might make the connection between Bruce Wayne and Batman. To forestall that problem, he hastily improvised a hood-like mask for the dog that incorporated the bat emblem as a dog tag dangling from Ace's collar. Ace was subsequently christened "The Bat-Hound" by a criminal he helped Batman to apprehend.

Wilker later took a new job that made it difficult for him to take care of Ace, so he left the dog to Bruce Wayne. Wilker was never aware that Ace was the Bat-Hound or that Bruce Wayne was Batman.

A modern-day version of Ace was reintroduced in Batman #462 (1991), although he has been little seen in recent years. This version originally belonged to a Native American shaman and had a distinctive bat-shaped patch on his shoulder. He didn't wear a mask, nor was he referred to as Bat-Hound. The dog at times helped Batman on cases, but disappeared after the events of the No Man's Land storyline in the late 1990s.