Maria was born in a time when her parents were both trying for the Embrace, and so she was ignored. After they failed and became bitter, she was treated badly. After she learned hedge magic all by herself and showed it to the clan elders, she was set for life. After her parents found out they raised a stink, so she was dropped off with the first available vampire cousin to await a proper age to become a vampire.
That happened to be Lucian. Uncle Lucian seems to be a nice enough fellow, a little more eccentric than even the rest of the clan, but what can you expect from a Giovanni who lives in Transylvania?