Every manga made by Go Nagai or it's spin-off and every anime adaptation of it are taking place in one Universe. Sait Universe is frequent victin of Reset Button
, starting again, upon reaching certain point in time.
We could see it with Devilman -> Violence Jack
-> Devilman Lady
-> Shin Violence Jack relationship, when some elements of previous world were carried out to the new one after the reset and in Shin Mazinger
, where Universe resets itself until Kouji defeats Antokui Daishogun
is also a part of this Universe, or rather it's 70's anime adaptation, that was existing in Shared Universe
with other 70s mecha shows and Manga version that has an crossover with Devilman, which means this world is a part of Getter-Multiverse