Meraud's Shield wraps a cleric in a mystical barrier that will absorb non-TM spells and counter them with a blast of divine energy that prevents the attacker from casting any magic(similar in effect to HULP, though I kind of like the idea of it being like Mana Disruption too). However, while Meraud's Shield is in effect, the cleric cannot use Harm Evil or Harm Horde.
"militantly enforcing the overly rigid standards of you and your small collection of friends"