Here are the specific informations:
For all shields, attacking GP'd creature with creatures is same as normal attacking.
Protect Field will have a same ability with sacrificed shield, so you can see what shield has sacrificed. For example, if Fire Shield has sacrificed, it will have "firewall" ability.
Dissipation Shield | Dissipation Field: If a creature is targeted with damaging spell, the quanta will absorbed and creature is not damaged.
Bone Wall: It get ?X counter(depends). If a creature is targeted with damaging spell, one Bone wall is spent. Gain 2 counter whenever a creature dies.
Skull Shield: All damage reduced by 1.
Gravity Shield: GP
Titanium Shield | Diamond Shield: All damage reduced by 2|3.
Thorn Carapace | Spine Carapace: All damage reduced by 0|1.
Fire Shield: GP
Ice Shield | Permafrost Shield: All spell damage reduced by 1|2.
Solar Shield: All spell reduced by 1. Absorbed damages are converted to
.
Wings: Creatures will evade ANY targeting from non-flying non-ranged source. For example, Otyugh cannot devour your RoL. Lasts ? turns(depends).
Fog Shield: Creatures have 40% chance to evade ANY targeting.
Procrastination: Any creature that damaged a creature will stuck in a time bubble for one turn. For example, EE will be delayed if it snipes your Armagio.
Dusk Mantle: Creatures have 50% chance to evade ANY targeting.
Dimensional Shield: Creatures will evade ANY targeting for ? turns(depends).
As you see, most of them will evade|absorb only damaging spell. However, some are not.
You or your creatures can target your creatures freely even under protection.