Somebody else mentioned this and I meant to explain and update-No Spoilers-
Long ago, before the first ape walked on land, great and hideous demons ruled the world. They were forced out of this dimension by various ancient gods. One demon, Cthon, left behind a powerful book of spells so that his followers could bring about his return(Presumably, Cthon was a Lovecraft fan). This book came to be called the Darkhold, or The Book Of Sin.
In the middle ages a cleric named Montessi somehow became immune to the Darkhold. He guarded the book. In addition, he created the Montesi Formula and bound it into the book. This spell was capable of destroying all vampires in this plane of existence. Later a scholar named Modred found the Darkhold. He was attempting to destroy Cthon, and actually succeeding, when his wife entered the room. In order to save her, Modred sacrificed his soul to Cthon. Modred ended up sleeping for a few centuries.
In the late '70s or so, the Darkhold and Modred popped up again. Modred attempted to bring Cthon back to this plane. He fought the Avengers. The Scarlet witch was briefly possessed by Cthon. Doctor Strange took possession of the Darkhold and found the Montessi Formula. He used it to rid the world of all vampires.
In the 90’s, Marvel revamped many of the horror comics of the 60’s. Something undid the Montesi Formula and vampires are back to their usual numbers. In addition, a strange dwarf(in the medical sense rather than the mythological. He lacked growth in the long bones.) was delivering Darkhold pages to people. While it took years of study to understand and use the Darkhold, these pages could be used by anyone. Simply looking at the page gives one knowledge of the summoning spell “Emmorath! Enamorath! Baal Set Elianath!”. This summons a green, shapeshifting entity which calls itself Other. The Other gives a brief description of what power the page offers, leaving out most of the details. If the person who summoned it accepts, they gain the page’s power in exchange for their soul. Victoria Montessi, a descendant of the ancient monk(who obtained papal dispensation to marry), has a vision whenver a page is used. Sam Buchanan is an Interpol agent who doesn’t believe in magic but has seen proof of a global cult dedicated to the Darkold. Louise (I can’t remember her last name) is a college professor and expert in mythology and the occult. They travel the world rounding up pages.
As whoever it was mentioned, they were plenty of guest stars. Modred returned. He's somewhat unbalanced by all he's been through, but he's generally an ally. Membership in the group changed. Various Big Bads began to rear their heads. A shocking revelation was made. Then, the series was cancelled. Some of the plotlines were continued in Doctor Strange.
Now The Full Version
Louise is killed. Her nephew, Jinx, replaces her. He was born with mystical abilities but their nature and potential is unclear. It turns out Victoria’s father is sterile. Thinking that as a Montessi he was immune to Darkhold’s corrupting nature, he used one of its spells to conceive Victoria and keep the Montessi family from extinction. This was a Big Mistake. Victoria recieves visions when a page is used because she is the dimensional gateway through which the pages recieve their power. Her existence is what makes the pages powerful enough for an average shmoe to use. Further, she discovers that she’s pregnant with Cthon. In 9 months, she’ll give birth to him and he’ll rule the world again. Doctor Strange agrees to help. He places her in temporal stasis. However, the spell fails to stop time and only greatly delays the end of the world. This is roughly Doctor Strange 65-70 or so, the same time as Strangers Among Us and the other arcs about Doc’s 2 clones-Dr Stevens and Strange. Sadly, I don’t know what happened to Victoria or any of the others past this point.
BTW-What happened to Morbius? For awhile his Midnight Sons revamp was excellent. “If I must drink blood, let it be the blood of the guilty. I will prey upon those who deserve to die.” No Anne Rice/Doctor Smith tragically hip vampire whining. Dark action and very dark humor. Then, they change his appearance and he looks like some evil-leather-fetishist elf. Then, the change him from dark predator who kills criminals to whiney Anne Rice/Doctor Smith “Oh, the pain! The pain of it all!” tragically hip vampire. IIRC, I cancelled my subscription at the same time the comic was cancelled. So, what’s the Living Vampire up to these days?