3. KATHERINE VON SWARTZSCHILD
While we know her as Katherine Petrova, her name in the books was Katherine Von Schwartzchild. Her family also had a German origin whereas in TVD series we see Petrova family having a Bulgarian origin. The creators make the change because the actress Nina Dobrev comes from a Bulgarian heritage and therefore can fluently speak the Bulgarian language.
2. DOPPELGANGER BLOOD
The blood of a Petrova doppelganger carries magical properties and has been used in numerous spells. Their blood can be in the binding of an extremely powerful spell as Esther used Elena’s blood and bound the life of Enhanced Original Alaric to hers, it can also be used in linking the supernatural beings with the help of magic which has been performed by a witch. While some spells specifically require that Petrova blood must be from a human, not any other species. Whereas some spells allow the blood of any kind of Petrova doppelganger.
The blood of the last two alive doppelgangers has been used in the Magic Purification Spell which resulted in Mystic Falls becoming a magic free zone. This spell undo all the spells which were cast using the non-traditional forms of magic which the Travelers deemed to be impure. This undo the spells of vampirism, daylight rings, and werewolfism.
1. PETROVA BORN IN EVERY 500 YEARS?
There has been a presumption that a Petrova doppelganger is born in 500 years. Klaus assumed that the Petrovas appeared in every 500 years because it took him that much amount of time to find the next doppelganger after Katherine escape him. This would mean there have been four doppelgangers of the Immortal Amara. The first unnamed doppelganger who was born in the 5th Century AD then Tata who was born in the 10th Century AD, it was her blood which was used in the creation of the Originals. Then came the third doppelganger Katherine who was born in the 15th Century AD, and finally Elena, she took birth in the 20th Century AD. And if we take a look at the Salvatore doppelgangers who come from the bloodline of Silas. The first doppelganger we are aware of was Stefan Salvatore who was born in 1846 then Tom Avery who was born in the 20th Century. So it just doesn’t make any sense. It’s an inconsistency on the part of the writers.
But this is wrong as Qetsiyah stated that both the Petrova Doppelgangers have taken birth in every century. In the episode ‘Original Sin’, the Witch Qetsiyah states that she has seen different versions of Elena and Stefan finding each other in every century. They have always been attracted to each other like the magnets. So the true number of the doppelgangers is unknown and the writers never addressed it. Klaus never found the other doppelgangers who were born in the time between.