Elsa Frankenstein is a name shared by two characters from the Universal Monsters universe.
Elsa Frankenstein (I)
Wife of Wolf Frankenstein and mother of Peter. Although she had great faith in her husband, she did not like the idea of moving from America to the town of Frankenstein, especially given the less-than friendly reception she and her family received upon arriving. However, the Baroness did eventually become quite friendly with the extremely polite Inspector Krogh, who would end up being her and Wolf's only dinner guest before they moved away again following the horrors that the deranged Ygor brought upon the family.
Elsa Frankenstein (II)
Daughter of Ludwig Frankenstein. She lived in Visaria with her father and was romantically involved with Erik Ernst, and was for most of her life unaware of the tarnished image of the Frankenstein name brought on by her grandfather, Henry Frankenstein (and in a small way, her uncle, Wolf Frankenstein). However, their idyllic life was soon disrupted by the arrival of Ygor, who blackmailed Ludwig into helping give the Frankenstein Monster a new brain. Elsa eventually learned the truth by reading the notebooks of Henry and Wolf, which Ludwig kept in his study.
When the Frankenstein household burned down as a result of the brain-swapping antics of Ludwig, Ygor, and Dr. Theodor Bohmer, Elsa escaped with the help of Erik. Despite being in love, it's obvious that things didn't work out between Elsa and Erik (no doubt due to all the horrors that came with Ygor's arrival), because Elsa was still unmarried by the time Larry Talbot arrived in Visaria with Maleva looking for Ludwig's notes, although initially he approached Elsa as "Mr. Taylor," pretending to be interested in buying her father's house, which Elsa was trying to sell. Dr. Frank Mannering soon followed, and it was discovered by all of them that the Monster had survived the fire.
Elsa, like her father, hoped to clear the Frankenstein family's name. But unlike Ludwig she did not intend to give the Monster a new brain. Instead, she made Mannering promise to use his surgical skills to destroy the Monster by dissection. Mannering initially agreed, but soon succumbed to the Frankenstein "curse" (despite not even being a Frankenstein) and instead rejuvenated the Monster using Ludwig's old equipment.
After breaking loose from its restraints, the Monster fought with Talbot, who had since transformed into his werewolf self. Meantime, one of the villagers, named Vazec, used dynamite to blow up the nearby dam and flood the ruins. With the help of a suddenly repentant Mannering, Elsa escaped the collapsing building with her life.