Is there any way to kill Alucard?
After the final episode, when Alucard returns after consuming Schrodinger and killing every other soul in his consciousness, he is, as described by Schrodinger, everywhere and nowhere, both alive and dead but at the same time neither. He can exist wherever he wishes, and thus theoretically speaking, he could exist inter-dimensionally, as well physically and consciously, implying that no, he cannot ever be killed. He will exist forever.