Katerina became a Vampire in 1492, turned by Rose-Marie's blood.

Which bloodline did Katherine come from?

Tatia is the first doppelgänger of the Petrova bloodline while Katherine is the second and Elena is the third and final doppelgänger. As of the eighth season, Elena Gilbert is the last living member of the Petrova family.

Who is Katherine's baby daddy?

In the season four finale of The Vampire Diaries, Graduation, Katherine slept with Niklaus Mikaelson and conceived her daughter, Adyelya.