Quoted By:
If we determine that polarity reversal of people is possible, it could end up being the key that unlocks the door for Talos to try it.
And also gives QM a reason for him to search of the fabled Ygma Monolith when we ever go to the Ultima Segmentum. Becuase perhaps all the Nulls on Xana and even our children may not be strong enough to permanently reverse Talos immense Primarch psychic aura, even if repressed. But perhaps something far stronger.
The 2nd Primarch visited the Ygma Monolith in canon.
"A new Warp storm near Oberon has been codified Cerberax – appearing as a three-headed hound devouring the sky. It has occluded a trio of star systems since the Night of a Thousand Rifts.The Holy Requisitioners of Mars have brought to light the effects of the Ymga Monolith, for extending around that rune-carved monument is a perfect sphere of order untouched by Cerberax’s progress across the stars. The Tech-Priests’last report describes that ancient stone as a Necron phase node of immense potency. Its glow has intensified so much it appears as a bright green oblong in the skies of nearby Atilla. I." - Gathering Storm II: Fracture of Biel-Tan page 18
Visiting an actual ancient Necron planet that later into the game could also be a good reason to kick off our untapped Chronomancy powers.