In the deepest memories of the Two-Typer species...always there were two kinds. Breeders and Hunter-Fixers. One kind made more of both kinds.
One aeon (right about now)..the Hunter-Fixers got more clever than usual about seeing and solving. They saw and solved and suddenly they had more resources available than anyone in their local stellar neighborhood.
Breeders seeing the "impossible" happening frequently began demanding more and more things happen for them to enjoy. When the hunter-fixers did not always produce these things active hostilities began. Hunter-fixer integrity was subverted and breeders attempted to absorb non-breeder functions. Chaos ensued.
Around the same time as Two-Type civilization moved off its homeworld breeder aggression was recognized by the warrior caste. Awareness spread and countermeasures were researched. Breeders were encouraged to consolidate present gains and enjoy their "victory" while Hunter-Fixers pushed the envelope in research and development of their counterstroke.
Complete duplication of critical breeder functions was soon achieved, and thereafter the old style breeder type was mostly found in various preserves and guarded environments where they were safe from hazards.
The breeder kind is highly celebrated among the culture of the hunter-fixers but strangely they all seem quite content to mainly use the technological replacements. Partial reproductions of breeders of varying historical accuracy and completeness are collectible items amongst hunter-fixers as well as "breeder experience" technology allowing hunter-fixers to mimick breeder traits.
There is speculation amongst the galactic mileu what would have become of the Two-Typers if the breeder type had not betrayed and made war on their species warrior caste and designated themselves as a credible existential threat. Hunter-Fixers still call themselves Two-Typers and insist they are "not truly a monate species" despite criticism from other species that the only Two-Types in their civilization are the Hunter-Fixer type and the Machine type (programmed to manifest in ways that seem Breeder-like).
Two-Type civilization areas dot the Arm and adhere to a fairly strict minimalism where the complexity of their artifacts are hidden from casual observation and use of nanotech is ubiquitous. The typical mode of address by Hunter-Fixer to their Network of Artifical Intelligences is typically the same ( allowing for dialect) as the now ancient mode of address by a Hunter-Fixer to the Breeder who created it.