There are four types of consumables:
Carmelite Water - your next usage of skill is free
Golden Elixir - remove all negative status
Royal Jelly - increases your effort point by 2
Devil's Thorn - reveal the vulnerability and immunity of the opponent
To use them, press the corresponding buttons above, and hold until the item is consumed.
This achievement requires you to use exactly one type of consumable each during a quest. I've replayed the quests a few times, and have so far found that only Quest 2 has alternate confrontations that give you a negative status. There may be others, but if you want this achievement quickly, you can do the following:
*** Spoiler - click to reveal ***- During Quest 1, ensure that you find all types of consumables. You can find them in the hall after the confrontation with the priest. There are a couple more in your bedroom before you sleep. Make sure you also use some effort points in Quest 1, and don't get them replenished.
- Start Quest 2, choose to help Washington.
- Go down to the hall, talk to the priest outside the salon.
- Enter the salon, intervene so that Elizabeth escapes.
- Enter the confrontation with Jacques Péru. You can hold for a free skill usage and to reveal his strength and weakness any moment during the first two sequences. You may also want to hold to recover 2 effort points now.
- During the last sequence, he draws a gun on you, giving you a negative status.
- Hold to remove the status, and finish the confrontation.
- Go back to outside your room. Finish the talk with the priest.
- Enter your room to end the quest.
Alternatively:
*** Spoiler - click to reveal ***- Choose to investigate your vision.
- Go the stairs area, and talk to the servant. Make him go make a tea for you by whatever means.
- Enter the room that the servant was guarding. Go out to the balcony.
- After eavesdropping, you'll automatically enter Emily's room via the balcony.
- Emily will set a knife on you, giving you a negative status. Hold to remove it.
- Finish the confrontation.
- Once outside, use all other consumables once.
- Go to outside your room, talk to the priest, enter your room.
You've now used exactly one consumable of each type during this quest. The achievement will unlock during the quest summary page. The achievement unlocks only after a quest is completed.
PS: Golden Elixir can only be used when you've a negative status, unlike the other consumables.