can deathwatch the spell counter....

[zainale]

invisibility or invisibility like abilities?

[zainale]

and can a blind person use it blind to see?

[EvilMinion]

I seem to recall a clarification somewhere that said that deathwatch only works on things you can actually see.
Thus no, you would not be able to see invisible things.

As to where that clarification is... um... This one, I believe.

[zainale]

cool just had to check.

[TriOmegaZero]

That's how I have always understood it. You need to be able to see the creature to get a read. So the undead disguised as a statue will be noticed, but the invisible assassin will not be.