From Destinypedia, the Destiny wiki
Splicer Captains are more deadly than their regular counterparts. For one, they come equipped with a Void shield unlike regular Captains, which have Arc shields. Second, their weapons have also been substantially upgraded: their Shrapnel Launchers have higher muzzle velocity; their Shock Rifles have higher fire rates and faster ballistic velocity; and they carry Scorch Cannons more frequently than their regular Fallen counterparts.
Known Splicer Captains
List of appearances