See: Decay and Valtorr.
The Verdant Vial of Valtorr was created because of a wager that took place one thousand years ago by the Octessence, eight mighty beings. They each put their power into an item and decided that the first mortal to come into physical contact with each being's respective item would become an Exemplar, possessing the power of the being who created the item they interacted with.
One Exemplar was Yoshiro Hachiman, the one who activated the Verdant Vial's power. He worked with the other Exemplars to fight against Juggernaut who had betrayed the will of the Octessence. But thanks to Captain America, who used Bedlam, Valtorr's influence was driven out of Yoshiro but the Vial still gave him its power.
Its current whereabouts are unknown.
It gave Yoshiro the ability to make organic objects turn to dust.