Alright so in d1 we learned Rasputin can control expos in a similar fashion as a submind, it’s an extension of him but still autonomous and independent, felwinter is his “son” in this way. While an exo in his first life felwinter died and we see this in the section of the lore and reads as “what’s going on,was I damaged in crypt processing? Who are you?” This is when he is also first resurrected by the light which left him with no memory which is what leads to the disconnection to Rasputin