What does the Parry Skill Do?

[Lazy_Perfectionist]

Yes. That one point of parry creates more shield hits, and the three protection lost are near irrelevant, considering most units will have trouble getting through 25 protection plus that of the body armor.

Between a black steel kite shield and a black steel tower shield, you'll only want to use the kite shield when you have mounted troops. If you're facing armor-negating weapons then you'll be best off without any defense penalty whatsoever- shield hits are useless though shields may still be useful for their abilities or protection from missiles.

The Weightless Shields you mentioned earlier has its advantages and disadvantages. First, its lower parry means it will block a few less missile attacks. On the other hand, the lack of defense penalty makes it more effective than the equivalent black steel shield in melee combat. Keeping the pure misses unchanged, but still decreasing the number of pure hits. The shield hits will be somewhat less safe, however, due to the lower protection, but the lower encumbrance means it you won't suffer the dangerous affects of fatigue - be it penalties to attack and defense and deflecting arrows or the deadly critical hit or dread vulnerability of falling asleep on the battlefield (relevant to super combatants and mages).

All in all, the weightless air shields are a better, but twice as expensive and harder to forge/research choice, then the blacksteel ones.