Wisteria

Wisteria is a plant predominantly used by the Demon Slayer Corps to combat demons.

History
Sometime in the past, a family was saved from demons by the Demon Slayer Corps. To express their gratitude, the family designed their family crest with a wisteria flower so Corps members would be able to identify the home, and stay there free of charge.

Usages

 * Wisteria flowers
 * Wisteria incense
 * Wisteria poison applied to weapons like swords and kunais, for highest effectiveness the poison needs to be adjusted for each individual demon
 * Wisteria antidote
 * Wisteria medication

Abilities
Ward off demons: By growing Wisteria flowers or burning wisteria incense around a house, one can ward off demons that would harm them. Gyomei Himejima always burned wisteria incense in his temple that was located in an area well known for demon attacks.

Trap demons: During Final Selection, wisteria is used to keep the demons trapped on Mount Fujikasane, hence the name "Fujikasane," which translates to "covered in wisteria". Demons are imprisoned inside the mountain to use as a test for would-be Demon Slayers.

Paralyze and immobilize demons: Wisteria can be used to create poisons which can paralyze regular Demons and immobilize Lower Ranks of the Twelve Kizuki. A normal dose of Wisteria poison on demons could hinder their abilities like regeneration, movement, suppressing their extrasensory perception as well as weakening their Blood Demon Art. In high enough concentrations, as used by Shinobu Kocho, these poisons are shown to be capable of dissolving almost any demon, negating their regeneration powers.
 * Shinobu Kocho primarily uses poison made with wisteria to battle demons, as she lacked the physical strength to behead them. To achieve this, her sword is shaped in such a way that it will inject a dosage into a demon through her Insect Breathing forms. Her sheath houses a supply of poison to keep her blade poisonous. Her poison is seen being used on Spider Demon (Daughter), killing her almost instantly after injection.
 * Hinatsuru possesses a box which is filled with numerous kunai laced with wisteria poison strong enough to paralyze normal demons half a day and even capable of immobilizing the Twelve Kizuki's Lower Rank demons. She attacked Gyutaro with darts that were coated with wisteria extract, causing him to temporarily unable to regenerate his feet. Tanjiro Kamado later stabbed Gyutaro with one of Hinatsuru's wisteria-laced kunai and used a courtesan's sachets to mask the wisteria's scent.

Alter human body physiology: With the help of Tamayo and Yushiro, Shinobu was also able to utilize wisteria poison in modifying her own body. In preparation against Doma, Shinobu willingly altered her own physiology so that every single cell of her flesh was laced with poison, with her body effectively becoming a undetectable, human poison capsule that would slowly destroy the body of even the highest Upper Ranks of the Twelve Kizuki with enough time once they devour her. As stated by her, with her bodies overall size and and body weight, she is 37 kilograms worth of poison, approximately seven-hundred times more than the lethal amount needed to kill an average demon.

Antidote against poison: When Zenitsu Agatsuma got poisoned by the Spider Demon (Son), Shinobu, with her unique antidote, saved the life of the former in an instant. Shinobu carries her medicinal pouch composed of syringes filled with Wisteria antidotes with her all the time.

Turning demons: Wisteria is also used by Shinobu to create a medication which would turn a demon back into a human.

Engrave Demon Slayer ranks: Following the Final Selection, wisteria is used to engrave the ranks of the corps members on the back of their hands.

Trivia

 * Wisteria flowers in real life are also toxic. The seeds of this flower contain a toxic compound called known as wisterin, which, if ingested, may cause dizziness, nausea, collapse, etc.