He doesn't really look like Deathwatch to me. More like Space Marine Captain + cool rules
Here's some Deathwatch equipment. That might differentiate him a bit from the masses.
http://wh40k.lexicanum.com/wiki/Deathwatch_Armoury#.UMSaIHfXsrg Change the Deathwatch rule to stubborn and preferred enemy (xenos).
Drop stubborn as it will be covered by Deathwatch
Drop Trained to Kill; that seems to be a bit excessive and it doesn't do much.
Leader of men is fine I guess. I don't really have a problem with it.