Tainted Grail: Conquest

By default, you start a run with 2 Healing Mixtures and nothing else. By clearing NPC encounters on the map, you have the potential to buy or earn other items that will be assigned to your combat quick slots. After you find the Scientist for your village, you will be able to receive items as drops from combat, as well as a shop in the village. The easiest way to do this is to wait until you have at least one more item, your 2 Healing Mixtures and have lost enough HP to use them both. Simply heal up, then use the extra item and this achievement is yours. Most items are single use and are lost on death, but the flutes you get from the Bard NPC carry across runs and can be used once per combat, so are a good "3rd item".