I have had the experience of sociopathic men and female friends conjuring the illusion of duality during the "lovebombing" phase (google that term if you need to) so I am not sure if I have ever experienced it, and I am not sure if I can tell them apart. But, I'm pretty sure my younger brother is my dual, we have always had an uncanny ability to "read each other's minds" and finish the other's sentences, almost like twins do, even tho we are half related.