Shin Mazinger Zero 

An alternative take on Mazinger Z, in the future, the world was destroyed by the demon know as Mazinger Z and the only human that is left on earth is Kouji Kabuto, he is given the chances to save humanity, by sending him back in time by a mysterious Minerva X, in this take the history is for adults, with nudity and blood that may be too much for some fans of the original version.