While that's somewhat similar to Alucard's role in Castlevania, Hellsing Ultimate's Alucard is anything but the kind-hearted son of Dracula. Another anime featuring Alucard is Rosario + Vampire.

but when it came time for Konami to begin working on Castlevania III: Dracula's Curse, the developers felt it was best for the series to return to its action-platforming roots; a decision that ...

In case you missed it when it first aired, the original Castlevania series follows vampire hunter Trevor Belmont, powerful witch Sypha, and Alucard as they take on Dracula and his demonic armies.