Find the Tower and loot the chest.
Loot and Tips
The Tower can be easily found due to the Crest of the Hollow Knights atop of it, along with Moonstone Blocks and its unusual design. You will face Hollow Knights of Fire and Hollow Knights of Thunder. The chest will contain 1 or more Energy Crystals and other drops based on the event's level. You may also grab several Crests of the Hollow Knights, which can be found on multiple floors.
- In case you don't want to face any of the creatures you can rush to the chest, loot and reenter the island. All the structures will still be in place but not the foes.