In Gigastructures, the entire galaxy gets fed to a Deep Shroud deity called the End of the Cycle. Vanilla Stellaris is a Recursive Reality where new universes are born from black holes.
The relative power of empires is evaluated on three factors - military power, technological progress, or economic power - allowing players to either specialize in a single area or maintain a balanced approach, with the ultimate goal being to either ally with or defeat every other empire in the game while surviving a ...
It is summoned using Worm Food from within the Corruption and Underground Corruption, or by destroying 3 Shadow Orbs that spawn in Corruption-filled worlds. It can be summoned at any time of day. Do note that Eater of Worlds shoots vile spit in Expert and Master mode.
A covenant with the End of the Cycle will pretty much spell the end of the game unless you are very good at coming back from the brink of destruction. Despite all its might, defeating the entity is not impossible.