This is an efficient card when it works but it doesn't always do something in every situation. The problem with this card is it requires a minion in play (outside of something like Tower Defense or Sinister Six) or it just doesn't do anything. It also makes your turn awkward since you wouldn't want to remove minions in play during your turn or you wouldn't be able to play this but you're not guaranteed to draw it so you're stuck in this dealing some damage to minions without killing it situation. Then if you don't draw it, the minion also gets to activate. Saving this card to use on the next turn also sucks since you're down a card for that turn.

When it does work though, this is great since it will still trigger a defense for things like Unflappable/Hard to Ignore/Electrostatic Armor/etc and guarantee taking no damage. But I don't think the upside is worth the effort.

This was updated in the 1.5 rules update to have the defense tag. This adds some value, eg. letting you pay for it with Nerves of Steel or picking it up with Jocasta.

SHIELDMAIDEN (#11) Should have the Defense trait and read: “Hero Interrupt (defense): When the enemy with Death-Glow attached attacks, declare Valkyrie the defender without exhausting her. She gets +2 DEF for this attack.” (Added “(defense)”.)

The classic chump blocker of protection.

On average, you will draw her turn 3, which leaves 19 cards in your deck. or another 3 turns. If you make sure to chump block with her, you will draw her another time or two before cycling your deck. As such, I like to see her as 2 to 3 allies for 1 slot. For many heroes like Groot that needs some form of block, she becomes very valuable. She also has the hidden quality of not going into the collection of the Collector I, being a literal cheat code to this difficult scenario.

One problem she has is that she doesn't have good traits or ways to discount her, she would almost be anti-synergic with Adam Warlock, and inconsequential in Strange, Scarlet Witch or Magik decks. Team-Building Exercise is therefore not effective. She can also not come online before the end of your deck, so she also needs to be backed up other chump blockers such as Starhawk or Honey Badger to beat the odds of not having her online before the end of the deck. You may end up not playing her when you draw her and loosing her recursive power.

Brother Voodoo can give you 2 thwart and a block for 3-4 ER. Most protection decks seem to run more than 10 events nowadays, so you should find one among the 5 you draw 80% of the time, reducing the ER of Brother Voodoo to 3. If you run more than 10 events that could be situational, Brother Voodoo also becomes a viable mini-tutor fetching the right event for the right situation.

To finish off, he is an Avenger, which is one the most developed trait now - you can cheat him with Avengers Tower, and Team-Building Exercise for only 1 ER, get a ready through Earth's Mightiest Heroes. It may also find a spot in a Drax deck, with Stand Together.

I love this card. In a deck with Giant-Man, he gets his attack bonus for one extra round. In a Cyclops deck, Wolverine can sit out this attack and heal. Essentially, any ally Voltron deck benefits from this card because it adds one more activation to whichever ally has the power you need this round.

Combine this with Go All Out and you can swing pretty hard while protecting an ally. Absolutely awesome.