Talk:Undead Machine Physiology/@comment-24053170-20160727024433/@comment-24053170-20160727025052

They completely gave up there organic bodies and transferred themselves into husks of living metal, and the process that trapped the C'tan in those same bodies destroyed there souls as well.

All they are now are soulless machine following the last mission they had before there souls were destroyed by the C'tan.

"Beginning the great biotransferance, the weak flesh of the Necrontyr was replaced with immortal bodies of living metal. The C'tan drank off the torrent of cast-off life and energy and grew stronger as Szarekh, now in a machine body himself, realised he had made a terrible mistake. The Necrontyr may now be immortal and unified, but they had lost their souls in the process. Thus the soulless machines known as the Necrons were born."

They are not undead, as to be considered undead there has to be some form of organics. but they are completely machine now.

This is taken from the warhammer 40k wiki.