Castlevania Legend Endings
Castlevania Legends has two different endings for you. The first ending depicts Sonia standing in the distance, as the castle crumbles to dust. You know the typical Castlevania ending. It tells of her being the first to vanquish the count, and speaks of another time where the evil might rise again. Thus hinting at Trevor Belmont. This is the ending below, and is widely regarded as the standard or bad ending.
If, however, you are able to acquire all the Mystic Weapons in the game, you will be privey to a very different ending. In this ending, Sonia is holding her new-born baby, and it speaks of the cursed fate of the Belmont Clan, and the destiny they will have facing Count Dracula again. It also speaks of the child being praised by the people as a hero. This of course has lent rise to the possibility that her son is indeed Trevor Belmont. And if that is the case, perhaps Alucard is in fact the father. This would easily explain where the Belmont's obtained their super-human powers. But that is of course just theory....