The girl who became Baroness Blood was one of the two daughters of village doctor Jacob Cromwell. A secret thrall of Dracula, Jacob was ordered to revive John Falsworth, who had worked for the Germans during both World Wars as the vampiric Baron Blood (see Baron Blood (Falsworth) )until he was staked and placed in the Tower of London. Jacob removed the stake, resuscitating Falsworth, who slew Jacob and one of his daughters, and transformed the other into a vampire. After Falsworth was again killed by Captain America (Steve Rogers) and Union Jack, Ms. Cromwell founded a cult dedicated to Blood's memory as the Baroness. At some point she met Axi Nacht (Gotteskreiger), who offered her membership in Axis Mundi if she would make a suitable sacrifice to prove her loyalty.
Learning the Holy Grail could render a vampire immune to sunlight, the Baroness had her cult search for it. Wanting revenge on the Falsworth family for opposing Baron Blood (Falsworth), she targeted Blood's great-nephew, Kenneth Crichton, who was dying from a rare form of anemia. She seduced Kenneth, turned him into a vampire, and dubbed him the new Baron Blood (see Baron Blood (Crichton) )before sending him to steal the Grail, which she brought to Glastonbury Abbey to perform the necessary ceremony. Union Jack arrived too late to stop her drinking from the chalice; the Baroness then broke it, leaving her coterie, Kenneth included, to be destroyed by the rising sun.
Having earned her membership in Axis Mundi with this sacrifice, the Baroness slipped away to give birth to Kenneth's son, whom she named John, after her vampiric sire. The undead infant inherited his father's blood condition, but could only feed off his own bloodline; apart from his mother, the only other potential food source was Kenneth's mother, Jacqueline Falsworth Crichton Spitfire. Alongside Axis Mundi, Baroness Blood (as she now called herself) attacked the Invaders; targeting Spitfire, Cromwell hypnotized her and was about to feed when the Axis Mundi teleportation system was triggered, taking the villains elsewhere. Returning to Britain, Baroness Blood sent some of her new vampire followers to attack the Destroyer (Aubrey), and as predicted, Aubrey called the Invaders; Spitfire was among those who came to investigate. The Baroness used hypnotism to take Spitfire captive, then informed her she would be used as food for John; however, Spitfire broke free, even as the other Invaders entered the caves, slaughtering the other vampires. Her plans thwarted, Cromwell teleported away with John.