David Cain

David Cain was a master assassin, servant of Ra's Al Ghul, former mentor to Bruce Wayne, former lover of Lady Shiva, and father to Cassandra Cain. Cain follows his own code of conduct and has but one loyalty; the highest bidder.

The assassin
David Cain is one of the world's premier assassins, whose victims have included some of the most famous and powerful people on the planet. He trained the young Bruce Wayne with the skills that he would use as Batman, although Bruce has never used such techniques. Regarding his training, Batman explained, "Knowing how to kill doesn't mean you must kill."

Cain desired a perfect partner with whom to carry out his assassination plans. Attempts to train young children resulted in failure, so he decided to conceive one himself. He found the perfect mother in a martial artist named Sandra Wu-San. He watched her and her sister duel at a tournament and concluded that it was her sister Carolyn that was holding Sandra back from her full potential. He murdered Carolyn and ambushed Sandra with the help of Ra's al Ghul and his League of Assassins. In exchange for sparing her life, Sandra agreed to bear David's child and leave the child in his care for him to train.

The child, Cassandra, would be Cain's "One Who Is All," whose native tongue was one-on-one combat and ability to read people's intentions simply by their body language. The latter was a special gift that only the Wu-San sisters and Cassandra knew. After bearing his child, Sandra set out to become Lady Shiva. His alias is Texas Dave.

The father
Cain trained Cassandra in every imaginable form of violence, from hand-to-hand combat to weapons and explosives. Cain never taught her to read or write; her only language was her ability to read people and predict what her opponents were going to do. When she was 8 years old, Cain took her to kill a businessman. After she did, she "read" him as he died, she saw death as the man saw it. "Terror and then... nothing". It was this reading that made her decide that murder was wrong and she ran away from Cain. Cain was first introduced into the Batman universe in the No Man's Land comic book arc. Two-Face hires him to assassinate James Gordon. Cassandra spots him and saves Gordon's life. After she has burned Two-Face's money to void the contract and refuses to come back to him, Cain leaves Gotham. He later broadcasts a video into the Batcave that reveals what Cassandra had done years ago, but Batman continues to trust her.

Framing Bruce Wayne
Lex Luthor hires Cain to frame Bruce Wayne for the murder of Vesper Fairchild. Cain's ulterior motive is to see if Batman was worthy enough of raising Cassandra.After the two engage in a fight near the end of the story arc, Cain believes that Batman is indeed worthy and turns himself in to clear Wayne's name. Luthor hires Deadshot to kill Cain while he is in jail due to a fear of him implicating Luthor in Fairchild's murder. Cain has a death wish and almost allows himself to be killed before reminded of Cassandra. He then fights back and nearly kills Deadshot (not killing him on purpose to prove a point). Cassandra visits Cain while in jail and attacks him, threatening to kill him if he ever committed another murder. Cain was proud of this and told Cassandra her birthday and said that "My little girl... all grown up." He once escaped prison undetected to give Cassandra a birthday present before returning.

Truth and consequences
Cassandra recently became curious as to the identity of her birth mother, believing it to be Lady Shiva. When she visited Cain in prison, he refused to tell her. Cassandra eventually confirmed her suspicions when she met Lady Shiva herself. As a result, Cassandra also quit being the super heroine Batgirl afterward.

One Year Later
Following the One Year Later continuity jump, Robin captures Cain and brings him to the League of Assassins as ransom to save Cassandra, only to find that that Cassandra is the leader. Cassandra explains that she chose to join the League because she found that Cain had trained other children in addition to her. Her actions were later explained to be the result of Deathstroke injecting her with a mind-altering serum. After her speech, Cassandra handed Robin a gun to kill David, offering him a place in her League. When he refused, she shot her father herself. Cain's final words are to tell Robin that there were other girls in addition to Cassandra and Annalea. Afterwards, Robin and Cassandra fight. The battle ends when an explosion causes a fire to break out. By the time Robin returns to where he had left Cain's body, it is gone and the assassins' necks are broken.

Batgirl
In the 2008 Batgirl mini-series, it is revealed that Deathstroke had given Cassandra the gun she used to shoot Cain, which was not fatal. After Tim and Cassandra started fighting, he got up and killed the ninjas himself. He hoped to open up an "assassination shop" with Cassandra as his second-in-command, using a drug that would turn his army into metahumans. He disappears when Cassandra murders the businessman who was providing that drug. Cain then plots with Slade to "cripple the meta-hero community." Cassandra, who used listening devices to overhear, believes that Oracle is the target of this plot and races to Platinum Heights, Oracle's base of operations, to rescue her. Cassandra locates her father on a rooftop and engages in one-on-one combat. He slides over an edge and is hanging by one hand. Cassandra contemplates whether to save him or not; when he falls, she attempts to grab him. She sees that he only fell a few feet to a ledge below, where he is arrested by Batman, who had followed Cassandra there.