The Mmrnmhrm were mechanical beings, that were churned out of the huge Mother-Ark about a millenia ago on some planet in the Virginis-constellation. The Mother-Ark was a huge factory ship send from an unknown origin, that created millions of sentient machines who called themselves "Mmrnmhrm", and then broke down.
In time the Mmrnmhrm met the Chenjesu and their co-operation and friendship became the foundation for the Alliance of Free Stars. After the Alliance lost to the Hierarchy, the Mmrnmhrm, along with Chenjesu, asked to be encased within a slave shield on Procyon II.
The Mmrnmhrm are no more, having been synthesized with the Chenjesu to form a new powerful race, the Chmmr to fight against the Hierarchy. This was a logical solution to them, for no more Mmrnmhrm could be made after the Mother-Ark shut down.