So let me restate the question another way: Whoever came first, out of all densities, what created them?
I do not think we can really answer this question from our viewpoint. In my understanding maybe DCM 'decided' to have the experience and let happen 1D to 6D. I do not think that we from 3D have enough insight to explain where and how DCM was coming into being. Maybe DCM existed 'always'. All densities maybe influence each other in some ways. Higher densities may just have more 'opportunities' for changes/influences than lower densities.
People I have heard of have 'stories' where God/a god/a being created our world. There are Native American 'stories' where there destructions changing our world from time to time and the humans were going from one world to the next. It seems to me that these are told due to a reason.
When time is an illusion then everything is happening the same time. It is just that we perceive past and future from our point of experience, but everything is happening in the present at the same time. I asked myself how could one send Reiki into the past. If time is an illusion then you just send Reiki to 'another now'. If/When 4D or 6D are doing changes to 'our 3D world/kingdom', they are doing the changes 'now' in 'The Present'. We may experience the changes after years, generations, centuries but they see the outcome at once.