The third entry to the Famicom Akumajou trilogy proves to be the best. Taking the gameplay of the original hit and adding to it, Akumajou Densetsu (Legend of Demon Castle) ends up being a true gem in the entire series. Akumajou Densetsu introduces new features that we see in later games, such as Dracula X for Super Famicom with multiple paths and the latest Game Boy Advance titles (Harmony of Dissonance and Aria of Sorrow) with more playable characters.
The story is set 26 years after the events that would take place in Castlevania Legends for the Game Boy -- Simon isn't born yet. The new Belmont, Trevor, is called upon by the people of Warakiya to help destroy Dracula, even though the Belmonts were banished after the fight with Sonia, due to the fear of their powers. Not showing any hard feelings, Trevor heeds the call and enters Warakiya to begin his adventure to stop Dracula. Though unlike Simon (his great, great grandson I believe), Trevor is not starting at Castlevania and instead has to take care of Dracula's Army around Transylvania. Because of this, he will need help, which comes in the form of three people.
Grant DaNasty, a pirate whose family was killed by Dracula and who previously fought Dracula but was beaten and transformed into a monster, forced to guard the Clock Tower.
Sypha Belnades, a magician with great powers, became a vampire hunter after having a bad life and wishing to fight the forces of evil, but she was turned to stone by the Cyclopes.
Then, there is Alucard (also known as Kid Dracula), the son of Dracula. He was awakened by Dracula to help fight Trevor, but Alucard, seeing his father's evil ways. He is more or less half human himself and like his mother. He rebels against his father to stop him. Previously, Alucard helped Sonia Belmont (Trevor's mother) fight Dracula and afterwards, hid himself away from the world.
These three are willing to help Trevor, but only one of them can join him during the game. Which one does so is your choice. If you wish, Trevor may also go alone, but it'll be a long and hard battle. The storyline is the best story for a Castlevania game thus far. With more than just a Belmont this time and the choice of using characters other than someone with a whip, there's definitely room for tons of fun here.