[Pathfinder201]

The primarchs were awsome and nigh unstopable. Why does the imperium not make more? It would mean that they would have an almighty general to comand them and they wouldn't lose and become extinct.

 

[darkreever]

The primarchs were created by the Emperor through means he never divulged to anyone, or those he may have died before they could pass it on (such as Malcador.)

Because of this, and the regression of the Imperium from developing new technology, there is no way for the Imperium to create new primarchs. Some more recent sources, like the Heresy novels by Black Library, may hint that the Emperor stole some power from the chaos gods in order to complete the creation of the primarchs. If such a thing is true, then it would further compound the attempts of anyone else to make primarchs at this point.

 

[Pathfinder201]

If only the emporor never had died and had just turned to chaos mabey the universe would be such a wierd place. It would be filled with nightmares beyond imagening but at least we wouldn't worship a corpse and be being destroyed by nids

 

[Akatsuki13]

The primarchs were awsome and nigh unstopable. Why does the imperium not make more? It would mean that they would have an almighty general to comand them and they wouldn't lose and become extinct.

Because only the Emperor knew how to create the Primarchs. No other man, save perhaps Fabius, knows the secrets of the Primarchs and their creation. The Imperium can't make anymore. But I doubt they would even if they could considering that half fell and became among the most dangerous of their enemies.

That is the greatest flaw of the Primarchs. Despite their immense superhuman abilities, they are ultimately human, with all of the inherited strengths and flaws that we all have. That was why Horus and the others fell. Their flaws and inner demons got the better of them and led them down the path of damnation, like so many others.

Any Primarch created by the Imperium now, would be human, just like the other Primarchs, which would mean that there would be the risk of them falling as well, becoming more threats to them. The High Lords would never take that risk, despite the benefits it would yield for them.

 

[Pathfinder201]

Then they should make a tau primarch because none of them have ever fallen. Though i do know this would never happen because they are against alliens

 

[Child-of-the-Emperor]

Then they should make a tau primarch because none of them have ever fallen.

The Tau could genetically enhance themselves or members of their race, but they couldn't craft beings that would be anywhere near as potent or immense as a Primarch. Its heavily implied (almost outright stated) that the Primarchs were crafted using not only the unparalleled genetical technology that the Emperor was privy to, but also the raw energy of the Warp/Chaos (something which the Tau could never harness).

And alongside all the reasons the above posters have given as to why the Imperium doesn't attempt to create new Primarchs, it would also be seen as one of the worst forms of Heresy and Betrayal.

because none of them have ever fallen.

PS. It is possible for Tau to fall to or be corrupted by Chaos. Some undoubtedly have, others are rumoured to have (Farsight).

 

[Baron Spikey]

And in the end, so what if a Primarch was made- they couldn't truly unite the Imperium in the Great Crusade, with a much weaker humanity in 40k the presence of a Primarch wouldn't save mankind, it wouldn't even slow their destruction.

 

[Tel Asra Nejoar]

wasnt there an attempt at it though? a secret one? i seem to remember a short story in which an investigation was being held at a secret facility that had been destroyed. it was discovered that the peeps there had made a primarch like dude, and then fabious turns up, wastes everyone and steals him or something. could even have been fan-fic, though i dont read fan-fic at all really...

 

[Baron Spikey]

It wasn't fan-fic it was part of the Index Astartes Cursed Founding article, but it was an improved Astartes not a Primarch.