Technicaly, Vlad Tepes was not a king. To have a king you need a kingdom, while the first romanian king was Carol I and he ruled in the 19th century.
Vlad Tepes was not called king ("rege" in romanian) but he was called "voievod".
He was the same as a king in Valahia (Walachia) or Muntenia but none of the romanian rulers could have the rank of king "rege" because of the foreign powers (the polish, the turks and the austro-hungarians) who wouldn't accept a king on the throne of any romanian country/province.
As I stated the first king "rege" not "voievod" camed in the 19th century.
Even "Mihai the Brave" who in 1600 managed to unite the three romanian provinces (Transilvania, Wallachia and Moldavia) didn't use the title of king as in "rege" but actually what pissed everybody off was that he used the title "principes daciae"(that's in latin and I'm not too good at latin) wich stated that he was the ruler of all the romanian provinces former known as Dacia until 106 AD.
Now back to Vlad Tepes, theoreticaly he was a rulling prince like all other romanian rulers wering titles like "voievod", "domnitor" or "domn".
Tepes was part of some kind of a royal family, having his father Vlad Dracul, his grandfather Mircea the Old (also ruller of Wallachia), and his cousin Stefan the Great (ruller of Moldavia).
More about Tepes:
He was raised in the Otoman Empire
He actually rulled the province twice, between them he made some 10 years of prison in Transilvania
He was assasinated in a forest called "Vlasia" near Bucharest were the 500 knights sent by his cousin Stefan the Great failed to protect him. He was ambushed in the forest by some 2000-3000 soldiers sent by the rival family of "Danesti".
"Liberate Tuteme Ex Inferis!"