The Synchronous Lotus is an essential resource you have to track down in Nightingale. You use it to craft Portals, and these give you access to new realms where you can explore for more resources and track down additional challenges.
You learn about what a Synchronous Lotus is as you play through the early main quests of Nightingale, but then you need to find them on your own. It can be troublesome to track them down, given the randomness of loot in Nightingale, though there are a few things you can do to help narrow down your search.
Where to find a Synchronous Lotus in Nightingale
When you first track down a Synchronous Lotus, it’s at the top of the Fae Tower in the second world you explore in Nightingale. From there, the first chest you unlock rewards you with the Synchronous Lotus, and you can take that back to your camp to craft a rudimentary Portal at your base.
From there, tracking down Synchronous Lotus becomes much more challenging. You have to explore the worlds you visit to find them, completing various challenges based on the ones that appear. For me, I was able to locate one by clearing one of the Occupation areas, where enemies had overrun it. After defeating them, I searched the chests for my reward, and a second Synchronous Lotus was inside.
Although these rewards seem randomized, don’t always expect them to appear in Occupation areas in Nightingale. I imagine that as you get a higher Gear Score and face off against more formidable foes, these rewards become much easier to find, giving you a chance to unlock more Portals. You can use your map to find helpful points of interest that could contain chests to loot, so long as you’ve explored the Fae Tower of the world.
The Synchronous Lotus is one of several resources you need to create a Portal. For your first Portal, expect to use Ingots, Wire, and Lumber. These resources will become more advanced as you find new Portal recipes in Nightingale and upgrade your crafting benches and tools. The Synchronous Lotus appears to be a fundamental resource for this building each time though, so expect to need to hunt them down quite frequently.