So many things are similar here: Character design; main theme(humans turning into monsters); smash cut zoom musical cues; and close ups on the eyes.
Given the fact that both series are the brainchild of Go Nagai, explains the similarities, as well as his expert way of telling so much with a mere close up of the eyes.
Spoiler: I found Devil Lady to be better with it's richer story line, but Dante has better plot twists.