Metalcraft is a new ability used by the Mirrans in order to unite against Phyrexia. It gives extra abilities or other bonuses if you control three or more artifacts which can include power and toughness increases, new abilities, or extra effects from spells. The nice thing about Metalcraft is that it always requires 3 artifacts so it is easy to take a quick look at the field and see if they are activated or not. The bonuses are also pretty nice, always being something that you would have to otherwise pay a bit more to use.
Probably the coolest use of Metalcraft is to surprise your opponents with powerful spells when you don’t have a lot of mana open. While counterspells usually cost 3 mana these days you can be ready for anything your opponent casts for 2 mana if you have three artifacts on the field and Stoic Rebuttal. I really like galvanic blast, which can deal an extra damage for the price of a lightning bolt. A lot of creatures are built around the 3 damage that lightning bolt can deal and an extra point can make a difference of life or death.
There are a few powerful spells with Metalcraft and their upgraded effects can really change the game but there are ways around it. Spells and triggered abilities with Metalcraft only occur if that player has three artifacts as they resolve. If you are facing someone that uses one of these abilities, try to melt away some of their artifacts. If you can get them down to two or less, you may have saved yourself and wasted some of your opponent’s cards!
If you are using an artifact deck with Metalcraft then you certainly don’t want this to happen to you. Once you’re at three artifacts it’s important to keep playing more, ensuring that Metalcraft triggers aren’t in jeopardy. This is important in decks with creatures like carapace forger that can become real threats around a lot of artifacts. Some good artifacts for this are those made of darksteel that are always indestructible. Other artifacts with Metalcraft are good additions to a deck, counting themselves when looking for artifacts. If you only have 2 artifacts on the field then a cool trick is to cast darksteel sentinel or another artifact with flash to activate Metalcraft and give a big boost to your creatures that will quickly give you the upper hand in many situations.
The Mirrans with Metalcraft, although it is their only ability in this set, are more than a match for any opponent. With the help of only 3 artifacts, many cheap creatures and spells become much more potent. But having just 3 artifacts will just leave your position vulnerable to the shatters and naturalizes of an opponent. Continue building a strong force of both artifacts and Metalcraft abilities to make a powerful united force that can stand up to anything!