Hero creation
During the design of the Project Titan — the predecessor of Overwatch, which was finally aborted before its release — the development team had thought of a class of heroes called the Guardians. They used their original idea to create Angela Ziegler, more commonly known as Mercy.
Before having the look we know today, Mercy had been thought of in a different way. Developers reused some elements of the Guardian class of the Project Titan to design her; the Resurrect Ability and the bundle of healing are the main ones. She was also renamed during the development of Overwatch. Originally, her name was Angelica and she had a teleportation power.
Her story
Angela was confronted with the horrors of war at a very young age. It was during an air attack that decimated a local Swiss hospital that her parents died. Rather than letting her pain turn into a thirst for revenge, Angela chose to turn to a more noble cause: helping people in danger and defending peace — thus paying tribute to her parents who had also chosen to take this path.
Very quickly, she gained a reputation as a young prodigy in the medical field and obtained her doctorate in medicine. In view of her skills, her reputation soon preceded her. She became a renowned emergency doctor before moving up in rank and becoming director of surgical services of a great hospital located in Zurich, Switzerland.
Her research in applied nanotechnology eventually led to a groundbreaking discovery that radically improved the treatment of life-threatening diseases and injuries. Thanks to her discovery, the medical care provided to patients was healing their wounds at an accelerated rate. It was this element that caught Overwatch's attention and prompted the organization to recruit her.
It was Jack Morrison (Soldier 76) — the leader of the organization at that time — who offered Angela the opportunity to join Overwatch as Chief Medical Researcher. Morrison assured her in his message that his medical research would not be misused, something Angela sometimes questioned after her integration. The young woman had the impression that the technology she had developed was being used and transformed for purely military purposes.
Despite her reservations and the many disagreements that persisted between her and the rest of the organization, Angela continued her work for the common good, eventually designing the Valkyrie Suit. Equipped with a digitization visor, propulsion system and biotic charges, the suit allowed her to fly over the battlefields and react quickly to crisis situations on the front lines.
After the fall of Overwatch, Angela regained her civilian identity as Dr. Ziegler helping victims and refugees in crisis areas around the world. Her guilt for the global suffering caused by Overwatch led her to Egypt, where she helped the wounded despite their disdain for her and all that her former comrades had done to their country.
After Winston's call and the struggle that took place in the city of Paris as shown in Overwatch 2 trailer, Angela could well return to work as Mercy.
Mercy's Recall Challenge is still ongoing and will end on December 2. Other unique rewards are to be obtained by watching Overwatch on Twitch.