The Dark Energy Crystals can go towards repaying the Quest potion I purchased that wasn't worth it. The Legendary Potion....I can not even use right now. My potion cabinet is getting full. I should at least be getting some legendary and gold foil cards when the new wave of cards are released. Or I would guess based on the pile of potions I now own.
If you are one of the few people on Hive not playing Splinterlands yet here is your chance https://splinterlands.com?ref=thejbullfrog