Maou Dante

Hamelin is more like fantasy and Dante is more modern, but all that brother|sister and demon|angel stuff is in both of them. But Dante is more connected with religion and Hamelin - with romance.  

they have similarity themes of apocalyptic events ... however the characters plot focus good within evil .... meaning to say that the story is focusing in the bad side that making it good side .. opposite in reality on what we learn in our society... 

Very similar animation style, storylines and character designs. Both are also from the same creator, Go Nagai. 

They're based on 70's manga preserving that typical action style and atmosphere. 

Both are based on 1970's manga from Go Nagai. Devilman is greatly inspired by Demon Lord Dante and Devilman would not exist without it. They both have a similar dark and gritty tone with lots of blood, gore and gratuitous nudity. As well as similar art and a similar vibe. The main protagonist in both titles are thrown into a life of darkness and must save humanity from demons. If you like one, you should enjoy the other.  

Both are based on 1970's manga from Go Nagai. Devilman is greatly inspired by Demon Lord Dante and Devilman would not exist without it. They both have a similar dark and gritty tone with lots of blood, gore and gratuitous nudity. As well as similar art and a similar vibe. The main protagonist in both titles are thrown into a life of darkness and must protect humanity from demons. If you like one, you should enjoy the other.  

Demon Lords??? Yes you got it both series focuses on demon lords. No need to explain furthermore. 

Both shows are extremely similar in overall plot and theme. The unique plot direction of both is the same, as is the romantic element. Going in to more detail on those elements would probably spoil various plot areas of both series' but after watching both, it is impossible not to compare them really and i thought of Angel Sanctuary frequently while watching Maou Dante. Both are also based on Manga's that were not finished when the anime was done (although Maou Dante actually had an ending made anyway). 

Both titles are based on 1970's manga from Go Nagai. They both have a similar dark and gritty tone, as well as similar character designs. Demon Lord Dante and Shuten Doji both feature the main protagonist that finds out that they are not human and are thrown into a life of darkness. They also have a good share of action, blood, gore and gratuitous nudity. If you like one, you should like the other. 

Both anime have similar animation, and a similar dark and gritty tone. Both anime were release the same year in 2002. Urotsukidoji: New Saga and Demon Lord Dante deals with demons killing humans and evil forces that are trying to start the apocalypse. They also have a good share of blood, gore and gratuitous nudity. The main differences between the two is that Urotsukidoji: New Saga contains graphic scenes of sex and rape while Demon Lord Dante doesn't.  

Different theme but there are some similarity. However when I watched them I felt Shinji and Ryo's action where similar also their fathers in some ways. The ending in Maou Dante is almost same as NGE: The End of Evangelion. Some of the romance may be same too. As NGE use mechas/Angels, Maou Dante also have some kind of huge alien/monsters or "Demons".