I should add that Scrap Code also refers to data fragments that can slow a Cogitator (like registry fragments that slow down your PC), redundant data files, malware, spyware, etc. and for most pertinent for this story, Viruses.

Viruses upgraded to the level of machine spirit!

Thanks for the info. But indirectly the Mechanicus worships the void dragon through the machine god, unless i'm mistaken. Thus the void dragon being a C'tan has incredible power, even though he's locked up, he can still influence machines, and the minds of the Mechanicus. It is mentioned that he started the cult on Mars by inspirating the first Mechanicus.

All C'tan have incredible mastery of the material realm and hate chaos. So why would he let his world, be over run with Chaos scrap code without a fight.

Maybe I just wanted to see a battle between chaos, and the void dragon suddenly showing his force. Lol.

He didn't start the Cult Mechanicus.
The Emperor did!

The Emperor was also the one who put the Dragon on Mars, most likely imprisoned in a Tesseract Vault.