In order to actually obtain this, you have to have 100,000 Essence on you at one time. If you're finding it hard to hold on to that much at once, you can face the Unknown alpha and Unknown beta monsters in the Towers of Folly, which gave me 7,000 Essence when I encountered them. I'll confirm whether or not they continue to give that much and append this at a later time.
Either way, if you solely stock up on Chocolate and clear every floor of an Ordeal, you should get this without even trying. Try not to spend so much on Fusing/Modifying Sentiments until later on, when you get Rare II pieces starting in Chapter 6 and 7.