Lisa

Lisa is Dracula's second wife and the mother of Alucard. Although never physically appearing in the Castlevania series before or since, her death serves as Dracula's motivation to wage war on humanity, finalizing his transformation into the main antagonist of the games.

It should be noted that Lisa is only ever referred to by her first name in the games; neither her maiden name nor what name she took when married (Cronqvist, Țepeș, or a pseudonym of some kind) have been established.

Background
Very few exact details about Lisa are revealed in Castlevania: Symphony of the Night and subsequent material. She was alive  sometime before the 1470's.

At some point during her life, Lisa met Count Dracula and became involved in a relationship with him. The reason Dracula fell in love with her was because she was the spitting image of his previous wife Elisabetha, who passed away during the time of the Crusades. From their union Alucard was conceived, inheriting the vampiric traits of his father and his mother's human heart.

Lisa created medicine for those who suffered from the epidemic. Due to the witch trials going during that time, Lisa was apprehended and executed. Dracula later found her body but arrived too late to save her. Alucard was present shortly before Lisa's death, just like his father, being unable to stop the event. Lisa delivered the following words for Alucard to deliver to Dracula:

''"Do not hate humans. If you cannot live with them, then at least do them no harm, for theirs is already a hard lot." ...She also said that she would love you. For eternity.''

Upon learning about his wife's death, Dracula vowed revenge. In 1476 he began his war upon humanity.

Castlevania: Symphony of the Night


Although Lisa does not make a physical appearance, the Succubus disguises herself as her in order to deceive Alucard. Throughout the castle, Alucard is able to rest in a coffin in order to his health and save the game. One of these save points, located in the Underground Caverns, is different from the rest. If Alucard rest in that particular coffin, the Succubus appears in his nightmare and recreates the moment of Lisa's execution, taking her appearance. The scene ends with Alucard seeing through the illusion and result in an encounter between him and the Succubus. Due to the death of the Succubus in the dream world, her soul is send wandering for eternity.