From the Temple Assembly Site, head through the Path of Eyes and Hive Chamber A. You'll encounter your first Inglet enemies here. Continue into Hive Chamber B, where you'll find the Dark Beam. This powerful weapon fires blasts of dark energy and is crucial for interacting with Dark Aether objects and enemies. Immediately after acquiring it, you'll be attacked by several Inglets. Use your new Dark Beam to defeat them, as it's highly effective against them.
The Dark Beam consumes Dark Ammo, which can be replenished by defeating enemies or finding Dark Ammo pickups. It also has a charge shot that can freeze enemies. Experiment with its properties. Once the Inglets are defeated, use the Dark Beam to activate the Dark Beam door in Hive Chamber B, leading you back towards the Temple Assembly Site. This new weapon opens up many previously inaccessible areas and allows you to progress further into the Temple Grounds.