I really like it. I don't think
Damian seems devilish at all.
I prefer
Damian over
Damien, because 1.
Damien was the spelling in Omen, I think, and 2.
Damien looks sort of femmey to me (like
Vivien,
Julien,
Adrien, etc) and those two things combine to give
Damien a sort of vampy character. I've know a guy named
Damian whose style was a little bit suited to the devilish connotation people find in the name (he was sort of a punk rocker I guess), but he was a manly person, not all fey and Damien-y.
(Apologies to Damiens everywhere - I've never met you, so this is just my impression of the name on paper. I think
Damien is a decent name)
I like
Damon even more than
Damian (it has the same origin). I know it's dated and associated with some dorky dudes, but that is kind of why I like it. It's more of a statement than
Damian is. Someone (New
Chloe?) said that it was "thuggish and slow, earthy and dense" compared to
Damian's "clarity, sparkle, energy, intelligence" and I agree with that impression (and I still like
Damon more!). I think
Damian sounds more modest and subtle, too. It's a great name =)