It is believed the Zentrians tie in with the multiverse theory, although no one has been able to prove this. Indeed, there is no scientific proof that the Zentrians even exist. Whether they are a race, an entity or a collection of spiritual beings is pure conjecture. The favoured explanation of conspiracy theorists is that they are an obscure ancient order and do very much exist in the physical realm, possessed of abilities that go beyond the bounds of scientific measurement.
A slightly less mysterious group known as the Obscure Ancient Order reject the hypothesis that the Zentrians are an obscure ancient order because, as Caspar Moonlake has rightly pointed out, this interferes with their marketing strategy.
Those that have been ‘touched’ by a Zentrian describe a rarefied presence that takes them away from time and space. They therefore cannot be affiliated with the Men in Beige, as the only thing anyone remembers after a visit from a MIB is being bored out of their mind.
From Doctor Boson’s Cosmogony – an encyclopaedia of the future