Succubus

Overview
In classical Western mythology, a succubus is a vampire-like demon that preys upon its victims through sex. The succubi in the CastleVania games, while they attack in sexually overt fashions, nonetheless behave more like typical vampires.

CastleVania: Symphony of the Night
Perhaps the most famous succubus in the CastleVania series is the one in Symphony of the Night. Located in the Catacombs, she hides inside a faux save point, where Alucard (the game's protagonist) is confronted by a flashback of the execution of his mother Lisa. However, presumably under orders from Dracula, the Succubus takes Lisa's form and attempts to seduce Alucard to the side of evil by changing her final words to him into a condemnation of humanity. When Alucard exposes her, the demoness fights him, but is defeated, instead condemned herself to 'wander the dream world for eternity,' in a rough transcription of Alucard's words.

Alucard himself points the succubus as a defiler and therefore says this: "Death is too good for you, defeated in the dream world will send your soul to wander for eternity"

Harsh words, but as Dracula could make an almost infinite amount of that kind of servants by turning pure womans into bloodthirsty vampires certainly is the fate of all the brides/fiances of the male heros of the game if they dont get rescued fast enough

Castlevania: Lament of Innocence
She is located in the Ghostly Theater disguised as Sara, Leon's fiancee, and tries to kill him with a knife. it is through her dying words that Leon learns of the connection between Rinaldo and Walter.

Castlevania: Aria of Sorrow
The Succubus in this game appears as a completely naked woman with bat's wings that attacks trying to suck Soma's energy. She will appear in the Top Floor and the Chaotic Realm. Her soul is an Enchant Soul that gives you the power to absorb enemy HP with every attack.

Castlevania: Dawn of Sorrow
The Succubus in this game appear in The Pinnacle. They take the form of Yoko Belnades, and when Soma passes them, they will kick him. Only by attacking Yoko's form will they turn into the actual Succubus. They also appear in The Abyss, but they don't take Yoko's form. Her soul is a Bullet Soul that gives you the ability to drink enemy blood to replenish your HP.

Castlevania: Portrait of Ruin
The Succubus in this game appear in Castle Keep & Burnt Paradise. They behave exactly like their Dawn of Sorrow counterparts, save for an outfit change and voice acting. They, like their Lilith counterparts, will say something depending on which character you fight them with. If you're playing as Jonathan, she'll say "You impudent!", and if you're playing as Charlotte, she'll say "Filthy cow!"