Castlevania III is the first in the series to offer multiple pcharacters to play. Your main character is of course a Belmont named Trevor. As you progress through the game, you might encounter a companion that will travel with you. If you come across another, you will have to choose between the two. It made the game a bit better for the player, to have a variety to choose from. Here is your cast of characters for Dracula's Curse:

Trevor Belmont
The famous line of vampire slayers, were banished from Transelvania because the people feared their great power. Now that the threat of Dracula has returned, they seek the aid of Trevor Belmont to destroy this unholy man.

Grant Denasty
Grant's family was killed by Dracula, and he was made a slave. Awake, but unconscious. He was set to guard the main way to the castle.Completely unaware of what was going on, he felt as though he was in a never ending nightmare.

Sypha
A vampire hunter, who uses the magical arts to slay the unholy terrors. He was sealed in the graveyard of Dracula's castle, to prevent him from interfereing with Dracula's plans.

Alucard
The rebellious son of Lord Dracula, Alucard has become hell-bent on ending his fathers lust to destroy the world, and fill it with his evil. Though half vampire, Alucard seems to have a great respect for the human side of his heritage. (this is not the last time you will see Alucard fight against his fathers evil forces)