The ancient spacetime-chemistry creatures, having survived yet another cosmic transition, gradually found ways to accommodate themselves to the latest climate, even though to them it was cold and dark and dead. In their heyday there had been no "matter" in the normal sense. But now they found they could usefully form symbiotic relationships with creatures formed of condensate matter: extended structures locked into a single quantum state. A new kind of being ventured cautiously through the light-filled spaces, like insects with "bodies" of condensate and "wings" of spacetime defects. It was the formation of a new kind of ecology, emerging from fragments of the old and new. But symbiosis and the construction of composite creatures from lesser components were eternal tactics for life, eternal ways of surviving changed conditions. In the unimaginably far future humans would call the much-evolved descendants of these composite forms "Xeelee."


The Xeelee are a hyper-advanced species from Stephen Baxter's Xeelee Sequence. They were first remotely mentioned in the 1994 novel Timelike Infinity and were later central actors of several novels and a substantial number of short stories. Within the Xeelee Sequence, they are considered to be the most advanced of all Baryonic life-forms and posses technology and abilities far beyond other spacefaring civilizations. They have demonstrated the ability to routinely construct Closed Timelike Curves and have engineered their own evolution and history as far back as 20 billion years ago (within two hundred million years of the Big Bang)

Powers and Stats

Tier: At least 4-C to 4-A | 3-C to 3-B, Low 2-C to 2-C | Low 1-C | At least Low 1-C, possibly higher

Civilization Type: At least Higher-Dimensional Civilization

Name: The Xeelee

Origin: Xeelee Sequence

Classification: Baryonic Species

Kardashev Level: Type VII (Exist and manipulate Configuration Space)

Age: Dozens of Billions of years, although technically inapplicable

Population: Unknown

Territory: All of configuration space which encompasses an uncountably infinite number of matter configurations of an uncountably infinite number of 10-dimensional universal domains

Technology/Abilities: Superhuman Physical Characteristics, Acausality (Types 3 and 4, type 5 for the Anti-Xeelee), Higher-Dimensional Manipulation, Mathematics Manipulation (Created a universe for the silver ghosts with different laws of mathematics), Spatial Manipulation, Immortality (Type 1), Higher-Dimensional Existence (The Xeelee are hybrids between organic beings and spacetime defects), Time Manipulation, Reality Warping, Law Manipulation, Technology Manipulation, Cosmic Awareness, Telepathy, Cosmic Awareness, Mind Manipulation, Soul Manipulation, Causality Manipulation, Abstract Existence (Type 1. Capable of existing as a metaphor), Pocket Reality Manipulation, Gravity Manipulation, Conceptual Manipulation (Type 2. Can manipulate the "light against which all phenomena are shadow" that forms all platonic concepts in the multiverse), Void Manipulation, Creation, Non-Corporeal, Resistance to Law Manipulation, Matter Manipulation, Information Manipulation, Conceptual Manipulation, Mind Manipulation, Soul Manipulation, and Perception Manipulation

Attack Potency: At least Star level to Multi-Solar System level (Starbreakers can destabilize and destroy stars by just grazing them and can drill holes through neutron stars. They launch thousand+ light year long cosmic strings weighing around a hundred billion times more than a star at speeds greater than 0.5c to cut galaxies in half) | Galaxy level to Multi-Galaxy level for cosmic engineering projects (Galaxies are used as construction pieces for large scale projects such as The Ring), Universe level+ to Low Multiverse level (Created nested static universes which means universes which are infinite temporally and spatially which is embedded in another such universe) | Low Complex Multiverse level with best technology (Capable of altering the entire multiverse to suit their needs. Capable of Altering configuration space, which contains an uncountably infinite number of matter configurations of an uncountably infinite number of finitely sized 10-D universal domains, where the 7 extra spatial dimensions are compactified to a Planck scale. Eventually managed to defeat the Transcendence, although it had been weakened) | At least Low Complex Multiverse level, possibly higher with the Anti-Xeelee (Exists in a noncorporeal state beyond space and time across all Configuration Space and is able to manipulate the quantum wave functions of structures within it. Likely comparable, if not superior to The Transcendence in nature and function)

Power Source: Black Holes

Industrial Capacity: Extremely High (The Xeelee can literally use space-time itself as a construction material)

Military Prowess: Individual Xeelee have merged with their own technology enough that any of them are capable of fighting. They have been at war with the Photino Birds since the beginning of time. However, they are relatively benevolent in the context of the verse and will even gift factions their own static universes should it mean they be on peaceful terms.

Notable Individuals: The Anti-Xeelee

Weaknesses: None Notable

Key: Conventional Weaponry | Cosmic Projects | Best Technology | The Anti-Xeelee


  1. The "Stupendous Number of Dimensions" in Configuration Space does not refer to the dimensionality of it, but rather the dimensions needed to map out the uncountably infinite number of interactions in it. Configuration Space is described as a Phase Space, and dimensions in a phase space only help quantify interactions in a system, not the actual spatiotemporal dimensions that physically make it up. These are just abstract mathematical modeling variables and are not to be used as tiering higher dimensions.
  2. The Universe in the Xeelee Sequence is claimed to be eleven dimensional, that being ten spatial + one temporal dimension. However the temporal dimension is an illusion created by the uncountably infinite number of matter configurations in Configuration Space and the extra seven spatial dimensions past our main three are compactified, that meaning they are bundled to be in a Planck scale and thus may not apply to any tiering metric.
  3. Stephen Baxter does not like using the term "multiverse" in his works due to his scientific background, so when he says universe it may either mean the observable universe, all the domains, or Configuration Space as a whole. To simplify debating, one should refer to each one as:
    1. An observable universe or domain for the finite universe itself, each one having slightly differing constants.
    2. The Universe or Configuration Space for well... Configuration Space.


Notable Victories:

Notable Losses:

Inconclusive Matches:


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