Tool Breeder (All Tomorrows)

The Tool Breeders were a posthuman species that evolved from the Swimmers.

Without the possibility to use fire, the Swimmers always adopted other species symbiotically to use them in place of conventional technology. In this way, they domesticated some creatures even before fully evolving sapience.

Later, this evolved into full fledged genetic engineering, with the Tool Breeders creating everything they need for their daily life from other lifeforms or later from stem-cells.

Their technological advances include:

Heart-like creatures that pump nutritional fluids into living buildings and machines

Shell-like buildings

Bio-luminescent lights

Cephalopod skin-televisions

Medical sea-squirts

Oxygen-filtering crustaceans for breathing under water

Mollusk-derived rifles that shoot out specially-modified "bullets"

Brain-augmented hunting-fish hardwired to return kills

Living starships

Living radio arrays, through which they made contact with the Satyriacs and the Killer Folk.

During the following ten million years, other posthumans joined in on the communications, including the Modular People, Pterosapiens and Asymmetrics. After another 20 million years, the empire also included the Saurosapients, Snake People, Symbiotes and the Sail People. Only after fourty million years, the Bug Facers joined in.

Over a timespan of about 80 million years, the Second Empire developed, through the combined effort of all members, into a galaxy-spanning empire, even though the members never met each other personally, and all of the species colonized other planets.

Though they were prepared to face an alien invasion, the Empire didn't think about an invasion from other posthumans, and so the Tool Breeders, along with all of their cousins, were quickly wiped out by the Gravital as part of their interstellar conquest.

Source: WikiFandom