'Nids Origin Theory

[dvs1]

Going by the timeline of 40k, I don't believe it's plausible that an old one created the nids to battle the c'tan and the crons. Mainly because tyranids weren't readily encountered by humanity until the time of the emperor, and even then it was more in it's recon- stage of development ( no hive fleet, mostly genestealers and related cults)The hive fleets did not become a problem until something like the early part of the 41 millenium. While it is speculated that there were in fact previous fleets throughout time, its not enough in my opinion to justify it only becoming a threat now. also, most other races would have long shared histories with the nids if they had a common creator ( much like how all the c'tan gods are in the nearly every races creation myths)
I would have to agree with the above posters that the nids look nothing more to me than super evolved locusts. They probably originated in a galaxy far from the one we know after consuming all the raw biomass in theirs. Since they come from such a far off place helps to explain their physiology being so different then what is usually encountered.

[sangrail777]

I got it. they where created by one of the unknown Primarchs then the other unknown chased him and his hordes out of the galaxy. But know they have returned.........no, a lil over the top huh. sorry. just came to me and thought it was funny. Or could it be true........

[Scoota]

Going by the timeline of 40k, I don't believe it's plausible that an old one created the nids to battle the c'tan and the crons. Mainly because tyranids weren't readily encountered by humanity until the time of the emperor, and even then it was more in it's recon- stage of development ( no hive fleet, mostly genestealers and related cults)The hive fleets did not become a problem until something like the early part of the 41 millenium. While it is speculated that there were in fact previous fleets throughout time, its not enough in my opinion to justify it only becoming a threat now. also, most other races would have long shared histories with the nids if they had a common creator ( much like how all the c'tan gods are in the nearly every races creation myths).

At the end of the Necron's codex, there is a little section that comes from Abaddon's perspective where he laughs at the MAchine Cult on Mars, as though he knows more about the 'Machine God' than humans do. If the Machine God is the Dragon C'Tan, then humanity only rediscovered the third Necron god recently (well, relatively).
It is possible that the Outsider could be the hive mind, trying to wipe out the food sources of the other C'Tan via the Tyranids, weakening them while It is feasting in another food-rich galaxy.

My money is on the Outsider as the Hive Mind.

[Grotzooka]

I don't know about the rest of you, but I really don't like the idea of EVERYTHING coming back to the Old Ones or the C'tan. It's just so much cooler to think that a huge creepy buggy planet-eating race evolved WITHOUT a crazy elf-in-space whipping up a brand new species. Not everything is interconnected, not everything SHOULD be interconnected.

[eldargal]

Exactly, less of the incestuous fluff. I think it makes for a far better story than the tyranids are a unforeseen and unplanned for interruption into the various pre-existing conflicts of the 40k galaxy.

I don't know about the rest of you, but I really don't like the idea of EVERYTHING coming back to the Old Ones or the C'tan. It's just so much cooler to think that a huge creepy buggy planet-eating race evolved WITHOUT a crazy elf-in-space whipping up a brand new species. Not everything is interconnected, not everything SHOULD be interconnected.

[Xas]

I like to think that the tyranids are the heirs of the Old Ones.

Some of them went for the run in time so they were able to escape. Then they crafted a new, perfect, self evolving bio weapon to combat their old foes. But their situation as a race was much worse thant he eldar's today and so they had no chance at surviving themselfes.

Instead of procretination they all ascended to an energy based semi-consciousness and together formed the omni mind that we know as the hive-mind. over the millenia more and more of the charachter of their servants has leaked into the consciousness of the hivemind, forming the hunger that is their main characteristic.

[mercer]

Evolved from another galaxy, as others have said, if the Tyranids had been around before they would have been mentioned i.e about Orks and Eldar working together when the Old Ones created them.