The name Alexander is derived from the Greek, meaning "Defender of the people" or "Defending men" and also, "Protector of men."
Corvin or Corvinus is a name assigned by Romanians to those who became warlords, nobles or even a king of Hungary. The first Corvin was John Hunyadi (Ioannes Corvinus), Voivode of Transylvania, Regent-Governor of the Kingdom of Hungary, who married a Hungarian countess.
Alexander's name in Hungarian is "Corvin Sándor."
Alexander is multilingual.
In the Underworld graphic novel, Alexander is mistakenly identified as being of 12th century birth, rather than of the 4th–5th century.
In the early fifth century, the Hungarian people lived near the south end of the Ural Mountains. See the map of Underworld locations. However, the Underworld films and novelizations imply that the Corvinus clan has lived in or near modern-day Hungary at least since the fifth century, before the Hungarian people arrived. Alexander and his children may have started identifying themselves as Hungarian later, in order to blend in with the new population.
It is unknown what would happen to Alexander if he was bitten by a Vampire or a Lycan. While Marcus and William were also immortals and yet became a vampire and a werewolf respectively, Alexander is the first immortal. So it is impossible to guess if he would have become a new kind of hybrid.
Alexander is the only immortal who's a human not a lycan/werewolf or a vampire