Seden are a race that transmit almost their full memories through inheritance.
They evolved to parasitically implant their eggs into Host Species (Rename), which are now extinct. Some facet of that creature's biology was irreplaceable, and led to the splitting of embryos with intact memories. Since then, they have not discovered a method to reliably split embryos without damage to the existing inherited memories - and a newborn without millennia of inherited memory is considered useless. As a result, the race is slowly dying out.
The Chtamadr Brood was capable of multiple embryos in the same cycle - some epigenetic switch was flipped and they adapted past the curse that is undoing their race. That bloodline was extinguished by its rivals, who saw it as a greater threat than glacially-paced population collapse.
This is par for the course, as the fallen empire has concerned most of its efforts on courtly intrigue and inter-brood rivalries. These have an added layer of complexity due to the length and uneven regularity of various broods' gestation times.
Their Parasite Empire (Rename) was a major intergalactic power, millennia ago. Some can still remember the glory of the empire's golden age, but they too are slowly dwindling.
They make use of public and private Pupatories for the purpose of gestation. They are administered and protected by Pupal Administrators (Rename) as a public good. As this is a vulnerable state and one that almost all citizens must go through, it is considered sacred.