ali81
MemberNeomorphJanuary 09, 2017now bare with me
the original engineers r a species that become a space travelling race at some point and explore theyr solar system. they come across a planet seemingly devoid of life until they go under ground and encounter the xeno (in some form) and believe it to be the perfect species. they begin to worship the species but over millennia they lose the ability to reproduce naturally, thus they delve into events such as beginning of Prometheus to repopulate the numbers required to sacrifice to the xeno life cycle, yet they don't believe in sacrificing themselves. a faction on another world becomes disgruntled that they r being used to keep this species thriving so rebel and reengineer the black goo to become a weapon of mass destruction on planets seeded by the engineers. the original population become aware and launch an attack on the facility on lv223 using the original xeno eggs, in the mayhem some of the local engineers r impregnated and xenos burst out and kill all the rest of the engineers (with the exception of at least one in stasis easily missed by those who cant open doors). now we don't see what becomes of these xenos as they find another, warmer part of the facility to start theyr nest as in aliens. the main engineers know better than to come back to the planet to tidy up and leave assuming all the rebel scum have been taken care of. plus the facility on lv223 was huge as we see by the scans so very little of the facility is actually explored by the crew.
just a theory that popped into my head
