Herb for All-illnesses

The Herb for All-illnesses (, Manbyō ni Kiku Kōsō—lit. "Herb Effective for Ten Thousand/All-illnesses") is a plant found in the Dark Continent. Its properties cause it to cure all kinds of diseases.

Overview
When the United States of Saherta sent their elite forces into an expedition to the Dark Continent, they went through the north of Lake Mobius and ended up in a sea of trees. After entering that for 400km, they found the ruins of an ancient city with a mysterious labyrinth. It was there that they found some herb(s) able to cure 10,000 different illnesses. They met Brion, the guardian of the ruins, that destroyed them effortlessly, leaving only two survivors.

Dark Continent Expedition arc
Ging Freecss narrates the five trips undertaken towards the Dark Continent, and mentions the herb to three members of Beyond Netero's Expedition Team, including Curly and Mascher.

Succession Contest arc
Steiner from the International Permit Agency (IPA) is appointed by the V6 as Beyond's guide. After boarding the Black Whale, he brushes up on the real destination of Dark Continent Expedition: the labyrinthine city where "The Botanical Weapon" Brion resides. He advises his cabinmates to do the same, since one of them will have to take his place if he dies. However, with the Hunter Association being in charge of security and the Director of the IPA being an official survivor of the Dark Continent, they are confident they will survive.