Added in Remnant II: The Forgotten Kingdom is a new questline that involves finding a newly found Kuri Kuri egg and taking it back to Ward 13 so that Duane can make the Egg Drink. However, there are a few steps to make that happen and items to be had.
How to Make the Egg Drink
Before anything, you’ll need to find the Kuri Kuri egg, which is found on the same level that you start on with you begin the Remnant II – The Forgotten Kingdom DLC. I’ve provided a guide below that shows you where to get the egg.
Once you have the egg, take it back to Duane. If he doesn’t take it, you’ll have to wait until Alice, the NPC in cross from him, is sleeping.
Once Alice goes to sleep and you have the egg, Duane will start a conversation with you, telling you he wants to make something different.
Hand over the egg, and he’ll tell you it will take a while to go save the world or something. This is basically telling you to go kill a boss. If you come back sooner, he’ll just tell you he’s working on a plan.
Once you’ve killed a boss, return to Duane, and he’ll tell you that you need an ingredient. He’ll actually do this several times, so it’s best to get the items ahead of time. Each time you give him an ingredient, he’ll tell you to wake. So go kill a boss again and return. If you run out of bosses to kill, you can reroll an adventure. Not to worry if you reroll the Forgotten Kingdom oneshot, as it won’t reset the progress.
Spicy – Ambit Ember, you can get that Drzyr Replicator on N’erud or Reggie
Sweet – Sweet Leaf, you can buy it off of the Walt NPC or Reggie
Kick – Strong Drink from Mudtooth
Once you’ve given Duane all the ingredients, he’ll thank you and give you the Egg Drink.
If you use it and need more, you can purchase it from Mudtooth.