What happened to Alucard after Castlevania: Symphony of the Night? (Possible Spoilers)
According to a Japanese-only, internet radio drama titled Akumajō Dracula X: Tsuioku no Yasōkyoku (悪魔城ドラキュラX：追憶の夜想曲) (Castlevania: Nocturne of Recollection), Alucard lived with Maria for a while. The script appears to play up the dedicated girlfriend/wife angle. The drama ends with them as a happy couple, more or less. There is no further mention of Alucard's life until his appearance in Aria of Sorrow.