Arthur Galston's Soil Knife

Origin
Arthur W. Galston (April 21, 1920 – June 15, 2008) was an American botanist and bioethicist. As a plant biologist, Galston studied the effects of light on plant development. He identified riboflavin and other flavins as photoreceptors involved in phototropism, the bending of plants toward light, challenging the prevailing view that carotene was responsible.

As a graduate student in 1943, Galston studied the use of 2,3,5-triiodobenzoic acid (TIBA) to encourage the flowering of soybeans, and noted that high levels had a defoliant effect. The British and U.S. military later developed TIBA into Agent Orange which was employed extensively in Malaya and Vietnam. Galston claimed that the creation of Agent Orange was something he deeply regreted, and later on he managed to convince President Nixon to make its use illegal after it was proven to cause both environmental damage that lasted decades, as well as birth defects in those exposed to the agent.

Effects
Holding the blade and concentrating on one's single greatest regret in life allows the weilder to undo that regret. However, this can and will cause a ripple effect stemming from that moment, effectively changing the timeline.

Storage
This artifact was initially stored in the Ovoid Quarantine after its collection in the 60's. While agents Scott and Nielsen were sorting a collection of artifacts for storage, Garrett recognized it's high risk of temptation and misuse by agents, and its obvious risks of timeline manipulation, and asked Mrs. Frederic if it could be stored somewhere safe. From then on, the artifact is kept in a multi-locked safe deposit box in the Restricted Chamber.

Trivia

 * This artifact has a high potential to be misused by the following current agents:
 * Arthur Nielsen, to undo the murder of Leena
 * Myka Berring, to undo the death of her partner Sam
 * Pete Lattimer, to undo the car accident that paralyzed a friend
 * Claudia Donovan, to undo the entrapment of her brother Joshua
 * Mrs. Frederic, to undo the death of her sister Justine
 * Garrett Scott, to undo the death of Chad Linwell
 * Scott, to undo the events of the Double Danger Arc (and his very creation)
 * Felix Draco, to undo the death of his fiance
 * Juan Horado, to undo the death of his childhood friend