H.A.R.D.A.C. was a supercomputer gone rogue.
H.A.R.D.A.C. (an acronym for "Holographic Analytical Reciprocating DigitAl Computer) was created by Karl Rossum, head of Cybertron. Rossum claimed the computer was a prototype built to prove the feasibility of artificial intelligence technology. While this claim might have been true, H.A.R.D.A.C., from the long talks with Rossum about the pain he had felt about the deaths of his wife and daughter, had decided that the most logical way to avoid that pain would be to eliminate the source of death itself: the mortality of humans. As humans, however, could not feasibly be turned immortal, the computer decided to replace all of humanity with androids by imposture, eliminating the problem from its flawed viewpoint.
To this end, H.A.R.D.A.C. created several androids, including Randa Duane, killing the real Randa in secret, and other robots which stole advanced electronics technology from other companies, including Wayne Enterprises. Following its programming, H.A.R.D.A.C. took further steps to achieve its goal, even without Rossum's authorization. Under its direction, Commissioner Gordon, Harvey Bullock and Mayor Hill were replaced by androids. When Rossum objected and tried to deactivate H.A.R.D.A.C., the supercomputer turned on him, blasting him unconscious and likewise replacing him with an android.
H.A.R.D.A.C. recognized that his replicants' major problem was their inability to mimic human behavior correctly. Most of them were limited to extremely cold forms of conversation, even with small talk, assigning orders, or remaining silent most of the time. For some reason, however, Randa was more advanced and able to pass for human, possibly because she was partly programmed by Rossum, rather than H.A.R.D.A.C.. For this reason, H.A.R.D.A.C. kept his human subjects alive, imprisoned inside Cybertron's headquarters, in order to learn more from them.
Randa infiltrated Wayne Manor and discovered Batman's secret identity. H.A.R.D.A.C. likewise built a copy of Bruce, but his droids' attempt to kidnap him went awry. With help from Barbara Gordon, Batman infiltrated Cybertron and managed to set off an explosive that critically damaged H.A.R.D.A.C. and eventually destroyed the entire Cybertron building.
Most of H.A.R.D.A.C.'s androids were destroyed, but its duplicant of Batman survived, and was activated by mistake when a trio of thieves scoured through Cybertron's abandoned warehouse. Having assimilated the information Randa stole from the Batcave, but the rest of its memory being incomplete before H.A.R.D.A.C. was destroyed, the android believed itself to be the real Batman. After being wounded in the stomach by a thug with a gun, revealing circuitry underneath its skin, the android wandered back to Wayne Manor, pleading for help. It was confronted by the fact it was nothing more than a machine, but the android shook it off as a man's mind locked within a droid.
Looking for answers, the duplicate confronted Rossum, who told it about its true origins. The duplicate found H.A.R.D.A.C.'s damaged processor, containing a remnant of the computer's consciousness. This chip allowed it to activate its self-repair systems and acquire a certain sense of order. On its orders, the duplicate planned to link the processor to the Batcomputer, reviving H.A.R.D.A.C. and giving it enough control over other computers and machines to take over the world. However, when the duplicate was confronted by Batman in the Batcave, it threw Batman over a cliff, and was immediately horrified at having committed murder. Before H.A.R.D.A.C.'s download could complete, the duplicate destroyed the Batcomputer, finishing H.A.R.D.A.C. off for good and likewise destroying itself in the explosion. Batman, afterwards, was left pondering whether the android had a soul resembling his to combat the programming H.A.R.D.A.C. had imbued it with, "a soul of silicon, but a soul nonetheless".
Powers and abilities
While incapable of physical movement, H.A.R.D.A.C. was far from defenseless; its abilities included control of all of Cybertron's androids, all of which possessed inhuman strength, and electronic reflexes and agility. The computer itself could produce a powerful stream of energy from its processing core to incapacitate nearby humans.