[Akimbo]

Just a few questions on this...

1) Does it matter which dragons you kill? The convo about the sword seems to suggest it does and that I should be killing Black Dragons for the blade.

2) What does using the sword do, it says "Do you want to take a drop of Dragon Blood" or something similar, but I didn't notice anything in my inventory after doing so.

3) Do I get to keep the weapon after handing in the quest?