Hmm, didn't get trough Elfen Lied, but I did like death note. I suppose Hellsing is a little on the 'happy go lucky' side compared to that. I think it's because Alucard seems to be impervious to anything, there's no challenge to him. But it's important to see that Alucard isn't the hero of the story. Seras, Integral and Bernadotte could be the heroes of the story. Some might even argue the Mayor is closer than Alucard. But that's covered in spoilers so let's not touch that. To be awfully honest Seras was a bigger influence on the creation of vampire Martin than Alucard was.