Some weapons were historically designed to penetrate armor like the crossbow, so you'll see an entry for "DR Pen": Damage Reduction Penetration: this removes some DR bonus, and if the DR Pen places target into negative territory for protect, then apply that as + to damage.

For example, if wearing a leather armor with a DR 1 (non-magical), and you are hit with a Lucern Hammer that has a DR Pen value of -2, it does an extra +1 of damage as it not only negated your DR for Leather on a hit, but its kinetic energy is amplified.

The crossbow's main advantage over regular bows was its ability to generate much higher draw weights - often 200-1200+ pounds compared to a longbow's typical 80-150 pounds. This massive force, combined with heavy steel bolts (often called quarrels), made crossbows devastatingly effective against mail armor and later plate armor.

Medieval armorers and crossbow makers were essentially locked in an arms race. As armor got better, crossbow technology evolved to counter it. They developed specialized armor-piercing bolts (or quarrels) with needle-sharp bodkin points, reinforced crossbow prods (the bow part), and mechanical aids like windlasses and goat's foot levers to cock these incredibly powerful weapons.

The crossbow was so effective against armored knights that it was actually banned by the Pope in 1139 for use against Christians (though this was largely ignored). It democratized warfare in a way - a relatively untrained crossbowman could take down an expensively equipped knight who'd trained for years.

For a list of armor, gear and equipment either consult PDF Armor and Gear of use Character Generator, tab 5 Equipment Character Generator

Armor DR is reduction of physical damage when taking damage. Does not apply to poison, disease, suffocation, mind effects, etc.

Negative DR value or a weapon's DR Penetration value, that brings your DR under 0 is + added damage.

All about Helmets

Helmets do not improve AC and do not add DR.

Instead, a helmet protects the head from serious injury when things go wrong.

A player without a helmet is always at risk when the blow lands in the worst place possible. Most of the time this will not come up. But when it does, it matters a lot.

Restrictions: Wizards and Thieves may not wear helmets. Helmets disrupt senses by dulling hearing, limiting vision, breaks concentration, etc. - making all abilities for those classes impossible while worn.

When head trauma checks should occur?

The DN may call for a head trauma roll when a natural 20 is scored against the character when attacked from above, or natural 1 is rolled when a character makes a Chance Roll, Save Roll or Probability Roll - related to potential body damage:

Examples:
A high fall onto stone or metal while attempting to walk on ledge (roll 1 on Chance Roll)
Forcing open a rusted iron gate which snaps and collapses overhead (roll 1 on Chance Roll)
A ceiling trap smashes down from above (roll 1 on Save Roll)
A rock, boulder, or heavy object drops onto the head (roll 1 on Save Roll)
A horse suddenly rears or bucks beneath a rider (roll 1 on Probability Roll)

If a character has no helmet, the DN should raise the stakes.

Possible consequences without a helmet?

When head trauma happens, DN decides and determines relative to scene.

Dazed - next turn is lost
Blurry vision - Quick saves are at risk for a short time
Ringing ears - Mind save rolls are harder until rest
Knockdown - character is stunned and falls prone
Memory jolt - forgets current action or spell
Complete blackout - lights out, body drops

Why players will want helmets?

A helmet will not stop blows like armor's DR and will not help you dodge like Dexterity Bonus.
It protects thought, balance, and consciousness when the world hits the head instead of the body.

If your cleric or fighter values their eyesight, balance, hearing, or consciousness, wear one.

Helmets Costs & Examples

Leather Cap - Thick hide or boiled leather, common militia wear. 3 gp

Padded Coif - Quilted cloth wrap that cushions blunt impact. 5 gp

Studded Cap - Leather helm reinforced with studs or bronze rivets. 8 gp

Nasal Helm (Viking Style) - Conical iron or steel with a nose-guard bar. 12 gp

Samurai Jingasa - Lacquered hat, lightweight, built for mobility and rain protection. 14 gp

Half-Helm (Iron/Steel) - Simple iron skull dome with reinforced brow. 15 gp

Spangenhelm (Persian / Germanic) - Sectioned iron plates with mail drape over cheeks and neck. 18 gp

Barbarian Horn Helm - Leather base with bone or antler crest, ceremonial and intimidating. 20 gp

Zulu War Helm - Woven reeds layered with hide, sturdy but flexible. 22 gp

Full Helm - Wraps skull completely, deflects strong blows more reliably. 25 gp

Lamellar Helm (Steppe Riders) - Overlapping metal scales, popular with horse archers. 30 gp

Khopesh Helm (Egyptian Bronze) - Bronze plate helm with flared rim and colorful plume. 35 gp

Norman Kite-Guard Helm - Sloped nasal helm with cheek plates, favored by early crusader cavalry. 32 gp

Tibetan Copper Ridge Helm - Copper and iron layered crown, wind-resistant and ridge reinforced. 38 gp

Armor Class (AC)

AC shows how easy (or hard) it is to land a hit when you attack with a weapon, fist, arrow, etc. Everyone starts at 10. Only shields, Dexterity ability bonus, magic items, or magic can raise or lower it.

Armor does not change AC. Even a knight in full plate can still be struck - AC is about whether the attack connects, while armor itself Damage Reduction: DR.

A shield gives a +2 to AC.

Damage Reduction (DR)

Armor protects by reducing damage once a hit lands. Types of armor has a flat DR value that is subtracted
from the physical damage taken.

Creatures, monsters, etc. may have a physical or magical component that raises their DR naturally.

Shields do not have DR and do not reduce damage. Shield raises AC, making it harder to hit you.
A natural 20 ignores DR completely.

Critical Hits

A critical hit when attcking, you roll a natural 20 on a 1d20. This causes two times more damage.
Critical hits bypass DR. No matter the protection, a perfect strike ignores all DR.