Simon Belmont is the most the most well known member of the Belmont clan, and is the protagonist of nine Castlevania games, though seven of the nine are remakes of the other two. Simon was the protagonist in the original NES Castlevania and its sequel Castlevania II: Simon's Quest. Five generations removed from his ancestor Trevor Belmont, Simon fought and defeated Dracula after he was resurrected in 1691. However, he was cursed by Dracula and did not properly dispose of Dracula's remains. Before the curse killed him, Simon had to collect the remains of Dracula and burn them in his castle. He collected the remains and defeated Dracula once again, freeing himself from the Curse.
Alucard is Dracula's son, and made his first appearance in Castlevania III: Dracula's Curse. He was born of a human mother and Dracula, but after his mother was killed he was corrupted by Dracula and trained in the black arts to become a powerful warrior. Being defeated by Trevor Belmont freed him from the corruption, and he went on to help Trevor defeat Dracula along with Sypha Belnades and Grant DaNasty. He went into a deep sleep, and woke again hundreds of years later when Dracula was again resurrected. With the help of Maria Renard, Alucard defeated Dracula once again and left to wander the Earth, where he would continue to battle against evil forces and would eventually meet Soma Cruz. He would help to unravel the mystery of Soma's Heritage, which he had particular interest in.
A legendary member of the Belmont clan, Trevor made his first appearance in Castlevania III: Dracula's Curse. Trevor is called upon to stop Dracula's conquest, and defeats him along with Alucard, Grant DaNasty, and his future wife Sypha Belnades. He was the first person to ever defeat Dracula, and the first to wield the mighty Vampire Killer whip. Trevor again appeared in Castlevania: Curse of Darkness where he was searching for a former servant of Dracula's named Hector. Trevor eventually befriends Hector after realizing he is not evil, but is wounded by another man and leaves Hector to fight and defeat Dracula.
A member of a group that watches over time, Aeon launches into action to prevent a disturbance in the tome stream by an evil entity attempting to take Dracula's throne. He makes his first, and only Castlevania, appearance in this game.
A possible descendant of Maria and Alucard, Eric inherited the mighty Alucard Spear early in his life. He made his first appearance in Castlevania: Bloodlines, where he helped John Morris to defeat Dracula during World War I. He would later father two daughters, Stella and Loretta, who would inherit his powers. He was killed by the vampire Brauner after Brauner bound Eric's daughters to himself to replace his own lost children. Eric held on as a ghost and helped Johnathan Morris and Charlotte Aulin defeat Brauner and eventually Dracula, freeing his daughters. He saw his daughters one last time before fading away. The Eric Lecarde in Judgment is very young, coming from the time before Castlevania: Bloodlines.
Maria Renard first appeared in Castlevania: Rondo of Blood. She was captured along with many other women from her village in order to be slaves for Dracula. However, the dark priest Shaft realized she had a special power and attempted to awaken it. During the ceremony she was rescued by Richter Belmont, and would eventually help him defeat Shaft with her magic powers. Five years later, Richter disappeared and Maria set out to find him. She eventually met Alucard in Dracula's castle, as well as a mind-controlled Richter. After saving Richter, she fled the castle and awaited Alucard's success at defeating Dracula. She may have eventually gone on to marry Alucard and had children, but it is a slightly unclear as to what exactly happened.
Grant made his first appearance alongside many of the cast in Castlevania III: Dracula's Curse. Grant was a pirate who went searching for Dracula after Dracula killed his family. He couldn't defeat Dracula, and was cursed. He was transformed into a hideous beast and forced to guard a clock tower, until Trevor Belmont came along and saved him. He swore to help Trevor defeat Dracula, and the group eventually gained the help of Sypha Belnades and Alucard and managed to defeat Dracula. Grant would leave the group after Sypha and Trevor married, as he had feelings for Sypha himself.
Originally coming from Castlevania III: Dracula's Curse, Sypha is a Witch capable of using elemental magic. She was called into action after Dracula summoned an army of demons in order to avenge his wife's death, but was soon captured by the demon army and turned to stone. She was eventually rescued by Trevor Belmont and Grant Danasty, whom she helped to defeat Dracula. She would eventually go on to become Trevor's wife much to the chagrin of a love stricken Grant DaNasty, and help to carry on the Belmont clan.
A witch who uses magical glyphs to attack, Shanoa made her first appearance in Castlevania: Order of Ecclesia. Shanoa was part of a clan dedicated to the destruction of Dracula in the absence of the Belmonts, and was to use the powerful dominus magic in order to defeat him once and for all. After Dominus was stolen by her former friend Albus, Shanoa tracked him down. He revealed that she had been fooled, that Ecclesia's leader was attempting to resurrect Dracula using dominus, which would have killed her. She confronted the master of the order, only to have him sacrifice himself to summon Dracula's castle. Shanoa managed to defeat Dracula, but the power of dominus required a life to seal Dracula. Albus sacrificed his life in place of Shanoa, sealing the dark lord.
A construct created by dark magic, a Golem has appeared in some form in just about every single Castlevania game in some form or another. Most often they're either very strong regular enemies or bosses that appear early on in the game. They've never really had any significance to the story until the Golem in Judgment.
A loyal vampire minion and servant of Dracula, Carmilla has appeared as a boss in many Castlevania games, though the first time she was significant to the story was in Castlvania: Circle of the Moon. She resurrected Dracula in her castle, but not at full power. Her plan was to sacrifice Morris Baldwin during a lunar eclipse to restore him to full power, as Morris has previously helped defeat Dracula. Her plan was stopped by Nathan Graves, Morris' apprentice. Nathan defeated and presumably killed Carmilla in the castle's sewers before going on to stop the not-yet-fully-powered Dracula. She appeared as a boss in Castlvania: Simon's Quest and Castlevania: Rondo of Blood as well, though she has no plot importance in those games.
Cornell is a member of a legendary tribe of beast men, making his first appearance in Castvania: Legacy of Darkness. He is a Werewolf, an is the only member of his tribe able to control his powers. His village is destroyed and he tracks the scent to Dracula's castle. He finds that his best friend has betrayed their village in order to get more power from Dracula. Cornell defeats him and attempts to rescue his sister Ada, but she is captured by Death. Cornell confronts Dracula and manages to save Ada, though he loses his beast power in the process. He does not defeat Dracula, but the two escape from the castle unharmed.
Death has appeared in pretty much every single Castlevania game dating all the way back to the NES. He is usually a boss fought later in the game, and uses similar moves in each incarnation. In recent games, starting with Castlevania: Symphony of the Night, Death has started to take a more active role in the story as Dracula's Second in command and servant. He usually seeks to help resurrect Dracula in some way, by either hindering the player or finding magical means to do so. He is characterized as being fiercely loyal to Dracula, and will defend him to the death.
The Dark Lord of the Castlevania Universe, Dracula is the primary antagonist in the series and appears as the final boss in almost every game. Dracula was originally human, a servant to God along with Leon Belmont. After his Wife died, her declared war on god and used a magical stone to steal the life of a powerful Vampire. He was first defeated by Trevor Belmont, who had the help of Grant DaNasty, Sypha Belnades, and Dracula's son Alucard. He would rise again throughout the ages of time, called forth by both prophecy and those seeking power. He would eventually be defeated in 1999 by Julius Belmont and die, only to be resurrected years later in the body of Soma Cruz.