Hush (Arkhamverse)

Hush, formally known as Doctor Thomas Elliot, was born into a wealthy family and was a childhood friend of Bruce Wayne, but, unlike Bruce, despised his parents due to his father's abusive nature and his mother's inability to control his father's temper towards him. Driven by independence and wealth, he cut the brakes of his parent's car which killed his father and severely injured his mother, who only survived due to the surgical skills of Thomas Wayne, Bruce's father.

Elliot was then forced to wait for his mother to die many years later to obtain the fortune, developing a violent and maddened rage towards the Wayne family, which would eventually centralize on only Bruce after the death of his parents. Driven by a desire for revenge against Bruce, Elliot has spent decades developing an elaborate scheme to ruin Bruce's life and satisfy his lust for vengeance.

Batman: Arkham Asylum
Although Hush doesn't appear, Doctor Thomas Elliot's night shifts appear on a duty roster hanging on the wall of the Surgery Room. Scanning his shift on the roster unlocks his bio. The duty roster confirms that he was recently treating The Mad Hatter and Firefly.

Batman: Arkham City
Sometime before the events of Arkham City, he was the one responsible for the surgery that separated Hammer and Sickle.

Hush appears early during the events of Arkham City in the Gotham Cathedral, which has been made into the new medical facility for the prison. After Batman rescues all the doctors and nurses from Joker's crew, Batman finds Thomas Elliot (although his name is not known at this point) on a gurney with his face covered in bandages and holding onto a crate. Another doctor, Adam Hamasaki, informs Batman that the patient was a doctor and amazing surgeon who transferred to Arkham City from Arkham Asylum. Over the course of several weeks though, Elliot stole various drugs and then cut his own face off. He was found by Adam while laughing in a corner and holding onto a crate, leading Adam to believe that the gifted surgeon had lost his grip on sanity due to the hellish nature of Arkham City. He wrapped Elliot's face in bandages, but was unable to pry the crate from the man's hands.

While Adam believed Elliot simply lost his sanity, the truth was far more insidious. In reality, Thomas Elliot led another life as a serial killer known as "The Identity Thief", who had been murdering people in Gotham City, surgically removing their faces, and storing them in a crate for his own purposes. Elliot's goal was to take the faces of individuals with similar genes as Bruce Wayne, with whom he held a personnel vendetta against, and surgically graft them onto his own face so that he could assume the identity of Bruce Wayne. After learning that several of his targets have been incarcerated in Arkham City, Elliot transferred to the super prison to complete his plans, starting with removing his own face and grafting the skin of his victims on his own. Now known as Hush, Elliot escaped the Cathedral while Riddler was abducting the rest of the medical staff and made his way to an old brownstone behind the Solomon Wayne Courthouse.

While on his mission to discover the truth behind Protocol 10, eventually, Batman pursues Hush while the killer murders several more victims to remove their faces, using several complex forensic methods to cover his tracks. Batman surmises that the murders are so well executed that the killer had to have been planning them for a very long period of time and is amazed when he learns that the finger left at one crime scene is a match to his own. This leads Oracle to speculate that Batman himself may be behind the crimes proposing he may've been poisoned by Hugo Strange or Scarecrow. Rejecting her idea, Batman continues his search.

In time Batman uncovers a third victim matching the same characteristics as the previous victims. While studying the crime scene he realizes that there are traces of bleach nearby. Following the trail, Batman eventually locates an Arkham inmate that said he'd been paid off by Bruce Wayne to dump the body and clean up the area. He reveals the location and Batman heads out to investigate.

When Batman finally tracks Hush to his hideout, he finds a disturbing and heinous torture chamber where Hush performed his inhuman experiments. It is revealed that Hush surgically altered his face, hair and his prints to look like Bruce Wayne by using the genetic similarities of his victim's faces, prints and hair in his quest for vengeance. He ends up escaping, with Batman commenting he will track Hush down the next night and closing his active case in Arkham City, and opens up a new one for Thomas Elliot, planning on investigating everything related to this former friend of Bruce Wayne and new enemy of Batman.

Trivia

 * This incarnation of Hush removes his victim's faces to graft a new one of his own, rather than using plastic surgery. This is similar to the character Jane Doe from the comics (rather ironically, Jane Doe removed Hush's Bruce Wayne face to wear as her own at one point).
 * It would appear his surgical disguise isn't 100% perfect, as he will noticeably press down and pull on his neck and throat and breath deeply as if trying to readjust it from time to time.
 * After hearing Adam's account of what happened to Elliot, the radio next to him will broadcast a story concerning Bruce Wayne's arrest and incarceration in Arkham City. Elliot will move his head suddenly and utter "Wayne" in anger after hearing his name, showing just how obsessed and vengeful Elliot is towards Bruce Wayne.
 * Unlike in the comics, where Hush debuted with a full knowledge of Batman's secret identity, he is unaware that Bruce Wayne and Batman are one and the same.
 * Elliot is only addressed as either Bruce Wayne, Dr. Thomas Elliot, and the "Identity Thief", never as Hush, implying that this is the first time Batman has fought Hush in the Arkham-Verse.
 * Despite the clearly visible surgical stitches on his face, Elliot is still mistaken by a large number of inmates to be Bruce Wayne. Although they did notice the stitches, they appeared to dismiss this as the wounds Wayne suffered fighting off his various adversaries.
 * In several locations around Arkham City, mostly near Hush's surgical equipment, there can be seen a green necklace. This could be a reference to Elliot's green necklace, which once belonged to his mother.