There are three Aegislash-Shield cards, according to Serebii's CardDex
Ability: Miracle Guard
As long as this Pokémon is in play, none of your Pokémon have any weaknesses
Attack: Protect Charge
During your opponent's next turn, any damage done to this Pokémon by attacks is reduced by 20 (after applying Weakness and Resistance).
A very useful card. As long as he's in play, none of your Pokémon have any weaknesses. It is best to keep this one on your Bench, as it's Ability if far more useful than it's attack. Attatch the necessary energy, and wait until the right moment to strike.
(Couldn't get an image, so here's the next best thing.
Ability: Stance Change
Once during your turn (before your attack), you may switch this Pokémon with an Aegislash in your hand. (Any cards attached to this Pokémon, damage counters, Special Conditions, turns in play, and any other effects remain on the new Pokémon.)
Attack: King's Shield
Prevent all damage done to this Pokémon by attacks during your opponent's next turn. This Pokémon can't use King's Shield during your next turn.
Another beauty, this Aegislash works great in tangeant with another identical Aegislash. On your first turn, use King's Shield. On the next turn, use Stance Change ro switch with the identical Aegislash in your hand. Since that is a different Aegislash, in theory you could keep using King's Shield every turn and be nigh invincible. I'm not sure if this is legal, I've been out of touch with the TCG for a while, but on paper it's spectacular.
(No image here, and no link. It's the Aegislash-EX card, btw.)
Ability: Mighty Shield
Prevent all damage done to this Pokémon by attacks from each of your opponent's Pokémon that has Special Energy attached to it.
Attack: Slash Blast
This attack does 20 more damage for each Metal Energy on this Pokémon. (Costs 3 Colorless Energy) (40+ Base Damage)
Probably the worst Aegislash-Shield card, this sucker's only advantage over the other two is his HP. Mighty Shield protects against Pokémon that specialize in Special Energy cards, making it a good counter for those types of teams. Slash Blast is a great attack, especially when used with Energy-transfer Pokémon. The more you Energy you gain, the more damage you deal. Simple!
I tried to answer your question as best I could, although it was a bit vague. I hope you can make use of this.