Maybe during yoga??? I've got one fundamental problem with my thought, what the hell did Rasputin attack if the darkness is what I said. I'll be honest, I don't have a good answer. But for Toland, he seemed particularly obsessed with ir yut and her deathsong, which in grimoire seem to imply the hive ability to survive death of time itself. If the darkness is the death of time, maybe the hive have figured out to survive it, basically eternally undead. So his communication with the darkness might be his realizing how the hive respond to it This would also explain while vex are aligned with the darkness. Their multiple timelines would allow them survival of the end time. The fallen and cabal? They are screwed...like us. Cept we are destiny ;)

According to one of Rasputin's cards (the ones in weird, military chatter) he comments that there are traces of dark matter/energy within the Darknesa

Actually it is the card that led me to this. It talks about neutrino scattering among other things. I honestly didnt know what that meant, so googled it. Said it was something that happens during a super nova. Hmm, Googled super nova....first hit "alpha Lupi"....Mind blown. Not saying I'm correct, but it was interesting.