They are quite tall and are adorned in very strong armor. They wield a large broadsword, as well as a scythe as a secondary weapon. Being very talented warriors, both in attack and defense, they can block most of Kratos' attacks, and deliver dangerous counterattacks.
Another subtle difference between the Captain, and the other Legionnaires is that their eyes create a streak of red when they move.
Kratos first encounters these deadly warriors in the Challenge of Poseidon, where an endless assault of Captains attack him while he tries to push the cage with the Sacrificed Soldier into the Chamber of Sacrifice. In God of War II, they only appear in the Lowlands Vista, and near the Courtyard of Atropos.
In God of War, after weakening it, Kratos can grab a Captain by the leg, and slam it in the ground. Then, to finish it off, he grabs its sword arm, and drives it through its back. In God of War II, the slamming is skipped, and a Quick Time Event is required to drive the sword through its back.
In the first game, the aerial grab move is the same that Kratos performs in all the types of Legionnaires and Undead Archers. In God of War II, grabbing a Captain in midair will make Kratos stab it with his both blades, pull it down, and slam its back on his knee, similar to a Wraith.