Extractor is an item, which allows you to get Soul Essences and Hate Vials if you placed it in inventory.
You need to kill bosses with >=50K HP for Soul Essences (33%) or >=55K HP for Hate Vials (10%).
Available after beating Moon Lord. Requires 10 of each celestial fragments, 100 of Emagled Fragmentations, 15 Luminite Bars and 15 Spectre Bars to craft.
It currently only works in Singleplayer.