A type of Macro-Cellular Silicone Life that lived on Homeworld.
One of the few types of Macro-Cellular Silicone Life to gain a noticeable degree of intelligence and the only one to gain consciousness complex enough for culture and inter-species communication. They have a unique capacity to not just have memories of how they experienced the past, but to actually see time as it exists along the Atomic Chains. This means they have an awareness of the past as it was when they were there and the past as it has become in their present, and an awareness of the current future and how it has changed over time.
On Homeworld they had migratory paths on the surface. Several of the excreted waste minerals were valued by humans who would protect migratory paths in order to collect said minerals. Lithos found this to be very awkward but didn't let that stress them too much. Along the migratory paths would be seasonal stopping grounds made of crystal and rock. These structures were old Lithos that root into the ground and form a collective conscious. Younger Lithos could form temporary connections to these and talk with the collectives. Humans were typically not allowed in these stopping grounds.
Lithos were valuable to humans for a number of reasons. Typically this took the form of humans fighting each other over rights to collect from migratory paths. It was rare for human squabbling to actively affect Lithos though and they were almost never enslaved or restricted. This was in part because the resources Lithos and humans sought were very different, but also because humans in general didn't want to disturb the production of valuable minerals.
The Galactic Magic Nullification killed all Lithos, though remnants of them could be found on Homeworld much later (see Past Extinction of a Forcibly Tidal-Locked Planet).