Ace the Bat-Hound

Ace was one of several dogs outfitted with playing card masks by the Joker and trained as attack dogs. Batman was bitten by Ace on September 2nd of one year.

The dogs were then abandoned in a pit for reasons unknown. When the dogs were found by Commissioner Gordon and Batman on September 23rd, the dog in the Ace mask was the only survivor, the pack having attacked each other.

Ace was transported to Gotham Pound. Two days later Alfred Pennyworth adopted the dog, despite the pound officer saying Ace's mistreatment had made him unfit to be a pet. Alfred gave the pound a large donation, in exchange for which he got Ace, and the pound was renamed the Martha and Thomas Wayne Humane Society.

Over the course of October and November, Alfred attempted to retrain Ace with difficulty, wearing a padded jacket due to the frequent attempts made by the dog to bite him. On December 14th, Bruce told Alfred he was wasting his time as "some wounds don't heal". Immediately after this, however, Ace responded to the command "Sit!"

On December 19th, when Batman entered the Batcave with a knife wound, Ace showed concern for him and stayed by his side.

That Christmas, Bruce gave Ace a mask, saying he could wear it at Halloween. He jokingly chided Alfred for not getting him a gift this year. Alfred was taken aback that Bruce did not realize his gift was the dog.