Shields are treated as an off-hand defensive weapon. Anyone with the shield proficiency can make an extra Active Defense die roll for their shield. A success means the shield was hit instead of its owner.
Shield Construction
All-wood and all-metal shields were very rare historically. Though role playing and computer games often depict shields made of wooden planks like picnic tables, or inch thick sheets of iron like manhole covers, most shields actually used in real life from the Classical (Greek and Roman) period though the dark ages and into the Renaissance, from one end of the planet to the other, were made of relatively light materials such as wicker, hide, bamboo, bone, horn, antler, leather, and cloth. \\
In some places like Europe, Persia, India, and China where heavier weapons and armor were often used, more substantial shields made of thin wood laminate, and incorporating metal bosses and sometimes rims were popular. In the Renaissance in Europe and South Asia some all-metal shields were designed. Most were bucklers but there were some larger examples such as the bullet-proof steel shields used by elite Ottoman Turkish infantry.
Hide Composite
These shields are made of leather or animal hide, with a wooden, bone, horn, wicker, or metal frame, and sometimes a wicker structure. Most very early era shields (such as during classical times) were made this way.
Wood Composite
These shields are made of thin layers of light wood with a total thickness of roughly ¼” -3/8”, usually with iron or bronze fixtures, notably a boss and sometimes a rim, reinforced with some hardwood struts, and often with a layer of linen or leather over the outside. Most European shields dating from the Classical era through the dark ages and well into the Middle Ages were made this way.
Metal Composite
Sheet metal over laminated wood, metal rim, and metal grip.
Shield Defense & Melee Weapons
The defensive bonus conferred by a shield in melee replaces and does not stack with that of any weapon carried, unless the carrier has the Shield Fighting Martial Feat.
In the latter case the shields defensive value can be combined with that of any S to M sized weapon also carried by the shield bearer (see Shield Fighting Martial Feat)