In BSG, it is said that the Final Five created the adversarial Cylons.
In Caprica, it is said the cylons originated thro Graystone technology.
So, who actually created the Cylons that wiped out the colonies? Graystones or Final Five.
It's all kinds of spoilery...
Technically the original Humans of Kobal created Cylons first. Possibly under a different name. At the time of the scattering (when Humans left Kobal), we had 12 tribes of Humans and one of Cylon. The Cylon tribe eventually gave us the 'Final Five', who traveled to a time near the end of the First Cylon War.
The Cylons made by the 12 Colonies are unique and different from those made by Kobal/composed of the 13th tribe.
As Dima technically states, Graystone Industries created a model of mechanical Cylons, presumably up to Model 12 (the original BSG models, just renamed and refitted), but the mechanical Cylons we know and love in the series were created by both the Graystone-style Cylons and the Final Five, meaning they're based off of both Colonial and Earth style designs.
The Humanoid models in the 2003 series were all created by the Final Five (again, as stated by Dima), and presumably are based off of the Earth-ian type Cylons.
Daniel Graystone's daughter, Zoe, uploaded a virtual copy of herself to V world.
Zoe then died in a terrorist attack set off by her friend.
In an effort to get Zoe back, Mr Graystone download her virtual copy into the cylon model he was developing for the military.
Graystone stole chip from his competitor, Vergis, to use in his Cylons. But still they didn't function as expected.
Zoe's program was used to make the cylon function properly (Mr grayscale was pressured into this by the military)
A variety of cylon models were created, from fighting in the military to taking dogs for walks to construction.
In BSG we only see the military versions. the above is from the TV show Caprica, basically Graystone created the cylons using a virtual copy of his daughter.
The last cylon model created by the colonials is model 0005. These are the cylons that declared war on the humans.
The war stops and for 40 years the humans see nothing of the cylons.
Meanwhile the cylon model 0005s have "evolved" into the modern sleek centurions we see commonly in BSG.
The centurions attempt to create skin jobs but fail succeeding only to create the hybrids (the hybrids are actually mutilated humans) The final five (having travelled from the original earth for 2000 years) persuade the cylons to stop fighting the humans in return for creating the skin jobs and resurrection technology.
All of the cylon raiders and transports are created by the cylons not the humans.
On the original earth there is a species that look like humans but are actually a type of skin job cylons (this is the species the final five belong to)
They created their own centurions who had their own uprising and seemingly wiped each other out.
The final five escaped using resurrection technology and went to warn the colonials but couldnt travel FTL.
The cylon war was restarted (I say war, I mean the destruction of the 12 colonies that we see at the start of BSG) when the first skin job model revolted against the final five, he wiped their memories and placed them on the colonies before the destruction.
at the end of Caprica we see Graystone create a skin job of Zoe. If you look closely enough this doesn't seem to be complete biological, more like a metal machine made to look and feel human. Also it is doubtful that this was made public as Zoe was considered a terrorist, and mr Graystone publicly says not to view cylons as humans. This is completely seperation to the skin jobs we see in BSG. It is also likely that the military would only want metal cylons given that metal makes a superior soldier, so the skin job was likely a once off to bring Zoe "back to life". However it maybe that the cylon centurions found that technology and Tryed to use it but failed before the final five arrived.
after the 12 colonies had created several huge ships that had all cylon crews there was going to be one of these huge warships for each of the colonies. this was to for eaches protection and to keep a peace. the ships did have one human in command. the colonies did this so that the cylons couldnt rebel and take control of the ship as you would need a human hand to activate the engines, and eye to acess the communications, other body parts to do other things. but when the cylons rebeled they knew that they needed these huge ships so they kept the human alive as best they could but in peices so they could control the ships. the colonies during the war destroyed three of the four that were made and the cylons had the other as their home. that was the ship that galatica fought to get Hera back at the end of the series. that is why there were trying to make the skin jobs. the one thing the colonies did right was make the ships and their programing to make the ships couldnt be done without a human element. thus the hybrid was created. that is why when the final five arrived they could end the war by giving the metel cylons the human made cylons so they could still build and acess certian parts of themselves and ships.the final five made the human looking cylons and the raiders of the same thing so that the human looking cylons would respect life and know that war was a last option. but the human cylons did what humanity did to the metal cylons and they enslaved them. thus again the running theme was reinforced, "this has happended before and will happen again." thats why in the end they were set free. but in all there are metal cylons out there still. the ones that were made on Kobol and maybe there were 2 types there the human looking ones of the final five and metal ones. and maybe one set was used and treated better than the other. so that is what could have happened to kobol. the 13 colony cylons (metal) recieved a signal and thats whats started them to go crazy prompting the final five to make preps to leave and thats what they did there was no loss in information for them from leaving kobol and settleing earth. as they used that tech for sometime until the evolved and could have babies. but also they were attacked from within and from without. as when the fleet ran into cylons that neither party of human and cylons and final five in fleet could not i.d. as to that they could not even i.d the ones they found on the planet that was unearthed with the remains of the 13th. so that woud mean that there are still cylons out there grauding something in a region of space where they will kill humans. and there are cylons out there who will maybe help humanity should they be found by the ones that hate humanity. but all in all the cylons were created by man and then cylons created man then man created cylons.... and in the the breaks there was a war as neither knew how to treat the other. cylons created man only to say that if the gods lived with man on kobol and gods live forever but can jump to thiers deaths would say that man created cylons human hybrids and know how to download organic memory into artifical bodies they became the gods the people on kobol worshiped. thus cylons created man. as the gods if they were somekind of human downloaded into artifical bodies they could have willingly forgot and ignored that they were once human. and if that is the case it would make sense for them making the final five kind as so they would have a servant class for them that could do things normal humans couldnt and were loyal as they were also children of the gods though maybe not as valued as humans due to breeding is easier that manufactuing (less cost). and this is why they all were able to leave together and were 13 tribes of kobol instead of 12 human tribes and 1 cylon tribe. this is why the colonies had a myth and semi respect for the colony as they children of kobol as well. the only problem is that in the 4000 years all 13 tribes did loose alot of info on kobol and each other. 4000 years yes... they either started to calculate time or they lost it.... kobol was destroyed they traveled and sublight speed to get to the colonies and then colonized thep planets there one at a time the 13 traveled longer and then colonized and lived and evolved the were destroyed and it took 2000 years for them to get to the 12 colonies and then we all know what happened. but at least 3000-4000 years passed but as advanced as they were they lost out on alot of info as the 12 colonies had to reinvent FTL and so other tech..... "but this has all happened before and will happen again"