Mark Tinta’s review published on Letterboxd :
Lesbian vampires were all the rage in the early '70s, with Hammer's Karnstein trilogy, the Spanish THE BLOOD SPATTERED BRIDE, and Jess Franco's VAMPYROS LESBOS to name a few. Harry Kumel's Euro arthouse DAUGHTERS OF DARKNESS might be the best of the bunch, a hypnotic, haunting erotic nightmare closer in spirit to LAST YEAR AT MARIENBAD than the usual commercial vampire fare, and not just because of star Delphine Seyrig as the Countess Elizabeth Bathory. It makes terrific use of one of the great horror movie locations (an empty, off-season seaside resort hotel in Ostend, Belgium), and there's some surface similarities to BLOOD SPATTERED BRIDE, chiefly a newlywed couple with more issues going on that they realize. The marriage of Stefan (DARK SHADOWS' John Karlen, later to play Tyne Daly's husband on CAGNEY & LACEY) and Valerie (Danielle Ouimet) is off to a rocky start, and it's exacerbated by the presence of Bathory and her companion (Andrea Rau). Stefan's got some serious issues of his own (watch him practically get off as he and Bathory engage in seductive dirty talk centering on Bathory's atrocities in one of the film's most perverse scenes), and his abusive, controlling tendencies don't take long to surface. And once we see his "mother" (a plot point that's left for the audience to interpret, which makes it even more unsettling) we realize that naive Valerie has no idea the degree of sexual and psychological dysfunction she's in for, and that life as a bourgeois vampire in the company of the eternal Bathory might be an appealing alternative.
I found this artsy and boring when I first saw it on the USA Network in the '80s, but it's really one of the great vampire films, and despite some occasionally wonky effects (that dummy impaling at the end could've used a second attempt), it's aged beautifully and gets better with each viewing.
"And by the way, Stefan...be sure to tell the young woman that Mother sends regards."