Revision 1

Hitotsume Gasa are a Genma type in Onimusha: Way of the Sword capable of wielding swords, bows, and shields. Capcom describes them as creatures that tend to attack in groups, driven purely by their basal urges to kill and devour people.

Equipment and Group Tactics

Their mixed loadout ties directly into the shipped combat toolkit. Shield-carrying Hitotsume Gasa need their guard broken rather than simply cut through, which is what the Combat System's Two-Handed Attack is built to do, and bow-carrying members can have their arrows deflected back toward their point of origin using the official manual's deflect timing.

The Genma article's description of unnamed shield-bearers and archers in the shipped game, enemies that turn aside plain sword strikes and open fire from a distance, describes this exact enemy type. Their bows also make the Oni Bow a useful answer at range, on top of a direct deflect.

Achievements

The game's achievement list ties directly to this enemy type. One achievement rewards breaking 100 shields or pieces of enemy armor, and another rewards deflecting 50 projectiles, both of which are most readily earned fighting Hitotsume Gasa's shields and bows.

Group Behavior

Because Hitotsume Gasa attack in groups rather than alone, encounters with them test crowd positioning and target priority as much as one-on-one technique. Leaving a bow-carrier alive while focused on a shield-carrier invites ranged pressure from the side, and clearing the group efficiently also feeds the Souls economy that funds the rest of Musashi's progression.