Enoch Leng

Enoch Leng was a 19th-century doctor based in New York. He was barely remarkable in his lifetime, but achieved posthumous notoriety when it emerged that he had killed at least thirty-six people while conducting surgical experiments in an attempt to prolong his lifespan—the largest serial killing in the history of New York City.

Early Life
Enoch Leng was born Antoine Leng Pendergast in New Orleans, Louisiana, around 1840 to Hezekiah Pendergast and Constance Leng Pendergast. He had three brothers: Comstock, a noted stage magician, Maurice, an alcoholic hanged for the murder of his wife and her lover, and Boethius, an explorer, archaeologist and the great-great-grandfather of Aloysius and Diogenes Pendergast. They were raised in the Pendergast's New Orleans family home, the Maison de la Rochenoire.

Antoine Pendergast was brilliant even as a boy. He was unbeatable at chess and backgammon by the age of seven, and later mastered the card game whist. Cornelia Pendergast suggested that some of his improvements to the game later helped its evolution into auction bridge.

Antoine was interested in natural history from a young age and kept a collection of specimens in his room. Unfortunately, he inherited his father's interest in darker substances including elixirs and poisons. He was said to have poisoned six family dogs during an experiment.

As a young man, he became involved with a woman named Marie LeClaire,undefined a servant at Rochenoire who was sixty years his senior. He studied the "Cajun voodoo" art of Obeah with her, and after she died, he exhumed her body and performed some unspecified ritual in an attempt to bring her back to life.

Exile and Relocation
After receiving his inheritance at the age of twenty-one, Antoine was banished from Rochenoire. He promptly moved north to New York and took on the identity of Enoch Leng, growing his fortune by speculating in railroads, oil, and precious metals, and disassociating himself entirely from his family.

In 1870, he applied for access to the research collections of the New York Museum of Natural History, listing as his qualifications baccalaureate and doctorate degrees from Oxford University in England and claiming to have been elected a fellow of the Royal Society. It is unknown if he actually attended Oxford or merely falsified his application.

He became a member of the scientific group known as the Lyceum and occasionally attended and gave lectures. Fellow Lyceum member J.C. Shottum found his knowledge of taxonomy and chemistry to be without peer. Shottum was impressed enough with Leng to allow him to rent the third floor of his museum, J.C. Shottum's Cabinet of Natural Productions and Curiosities, as a laboratory. He later became suspicious of Leng, broke into his laboratory and read his experiment journals.

Shottum discovered that Leng had been kidnapping visitors in an isolated corner of the Cabinet and killing them to extract chemicals for a serum he believed would stop the aging process. In the coal tunnel underneath the building, he discovered Leng's victims; one was still alive. Shottum confronted Leng, and Leng presumably killed him and burned the Cabinet to the ground to cover his tracks. The fire was ruled an accident caused by a faulty gas lamp.

Leng moved his laboratory to Doyers Street, setting up shop in an abandoned waterworks. He volunteered his medical services at two nearby workhouses, where he could find a constant supply of street children for his experiments. There he eventually perfected his arcanum and managed to stop aging.

At some point, Leng acquired a large Beaux Arts mansion at 891 Riverside Drive in Manhattan. He renovated the house extensively to recreate the layout of his childhood home, Rochenoire. When Aloysius Pendergast found the mansion, he was able to navigate it largely from his own memories of the house he had inhabited and explored as a boy.

In 1917, the building housing Leng's laboratory was destroyed. He moved his laboratory into his home but continued to kill and dumping their bodies in tenements, at the rate of approximately one victim every two years. In about 1930, he learned how to create the arcanum synthetically and no longer had to kill to obtain the ingredients.

Having staved off death indefinitely, Leng was able to focus his attention solely on his original goal: he had long since decided that humanity itself was a cancer on the earth, and resolved to create a substance which would destroy the human race. He experimented with fast-acting poisons from a variety of sources, with delivery methods ranging from aerosols and conventional weaponry to household items like umbrellas and clothing. He continued this research for many years until March 1, 1954, the date of the Castle Bravo hydrogen bomb test. On that day, with the advent of nuclear weapons, Leng became satisfied that humanity would eventually wipe itself out, and abandoned his research. He stopped taking his arcanum and allowed himself to age normally again, keeping a single written copy of the arcanum's formula hidden in the walls of the house.

Death
By the events of The Cabinet of Curiosities, he had not taken the arcanum for several decades and had become old and decrepit. An immortality-obsessed killer that the press would later dub "The Surgeon" had learned of Leng's work through the archives of the New York Museum of Natural History, located the Riverside Drive mansion and found Leng still living inside. He eventually resorted to torturing Leng to learn the formula for the arcanum, but Leng died before revealing his secrets.

His body was discovered by Special Agent Pendergast and Nora Kelly, and was presumably interred at the family plot at Penumbra Plantation.

Constance
In the late 1800s, Leng took in as his ward a young orphaned street urchin, Constance Greene, from one of the missions where he volunteered. Constance's sister and caretaker Mary Greene was one of Leng's victims, and it's possible that he adopted Constance out of guilt for leaving her alone in the world.

Leng educated Constance and gave her full access to the scientific collections and books in his home. He also gave her the arcanum, extending her lifespan far beyond the norm. She continued to take the serum even after Leng decided to stop, barely aging at all between the late 1880s and The Cabinet of Curiosities. After Leng's death at the hands of The Surgeon, Constance hid in the subbasement of the mansion while Wren catalogued the contents of Leng's collections, eventually revealing her presence and becoming Pendergast's ward.