Notes from author
Alrighty. This build has two pillars holding it up.
One: Pushing with shields (WHILE NOT TWO-HANDING THE SHIELD) takes the defensive properties from whatever is in the left hand.
Two: Attacks and shoves from shields, in the main hand, have block frames which count as holding the block button. Shield attacks have block frames at the end of their animation, while pushes have them throughout the duration of the animation.
Knowing these two things, while wielding the Pierce Shield, makes it very easy to capitalize on both instability damage, and counter damage.
Attacking after a push will grant, roughly, 40% extra damage.
Additionally, utilizing the Pierce Shield's block frames and status as a thrust weapon, one can attack DURING an enemy's attack for, roughly, 60% extra damage (20% from thrust and 40% from the Leo Ring), while only taking minimal damage.
In the left hand, we have the Crystal Shield (100% phys and decent lightning/fire resistances), and the Crystal Ring Shield (90% magic resistance). Primarily used for pushing.
The equipped armor grants enough poise to resist a stagger from any one attack. This is just a safety net to prevent stunlocks from failed block frames.
Important Stuff:
Magic Weapon CANNOT be applied to shields.
Magic Shield CANNOT be applied to shields in the main hand, but shoving, with a buffed shield in the off hand, will use the spell's properties.
The Pierce Shield's block frames are longer, on strong attacks.
[Sources]
http://www.youtube.com/watch?v=nIILl_qH_h0
http://darksouls.wikidot.com/counter
http://darksouls.wikidot.com/stagger
