Xeelee
The Xeelee are a fictional alien species appearing in the science fiction works of Stephen Baxter. They are an ancient and powerful race, primarily known for their role in the Xeelee Sequence, a series of novels and short stories that explore vast cosmological themes and humanity's place within them. The Xeelee are depicted as being incredibly advanced, having existed for billions of years and having witnessed the birth and death of stars and galaxies. Their motivations and biology are often enigmatic, and their presence in the universe is associated with massive, cosmic-scale engineering projects.
One of the defining characteristics of the Xeelee is their profound influence on the universe's development.