[Update #2]: MTG Arena's Phyrexia: All Will be One expansion has now arrived with plenty of poison and proliferation.
[Update]: Explorer Anthology 2 and Alchemy: The Brother's War expansions have now arrived with staples and jank galore.
In celebration of its 30th anniversary, Magic: The Gathering has now unleashed The Brothers' War expansion onto MTG Arena. This new Standard set brings with it a bunch of cards detailing the great war between Urza and Mishra, an absurd amount of fancy new artifacts to toy around with, as well as reprints of some of the most iconic artifacts from across all of Magic's history.
When it comes to the actual mechanics behind the cards, there are four major ones you'll need to keep an eye out for: Meld, Unearth, Prototype and Powerstones. Here's a brief rundown of what each of them does:
Prototype - Cards with Prototype are generally incredibly powerful, yet also expensive to cast. In order to make this less of a crippling downside you'll have the option to either pay the exact mana cost in order to get the creature at its full power, or pay the smaller Prototype cost in order to get a creature with the exact same abilities but with a weaker body.
Meld - True to its name, Meld allows you to combine two cards into a significantly stronger one. In the case of The Brothers' War, the main purpose of Meld is to showcase the incredible power wielded by some of the major characters like Urza and Mishra.
Unearth - By paying the Unearth cost you can bring back creatures from the graveyard to the battlefield with haste. They won't be sticking around for long, however, as creatures reanimated with Unearth will be exiled either at the end of the turn, or whenever they leave the battlefield.
Powerstones - A Powerstone token is a colorless artifact that can be tapped for one colorless mana. The catch is that the Powerstone mana can't be used to cast a non-artifact spell, though you can still use it to pay for activation costs or triggered abilities of non-artifacts. It's a simple yet versatile design, especially in Limited formats.
What all of these mechanics and ideas look like on actual cards, that you can check out over at official The Brothers' War card gallery. Wizards of the Coast has sorted all of them by color, with the appropriate Prototype cards nestled at the bottom of each section, so it should be fairly easy to figure out what each of the color combos is going for.
As for the previously mentioned artifact reprints, those will follow the same rules as Strixhaven's Mystical Archives and will replace a random common card in each pack. So not only will you be getting more powerful cards than usual in The Brothers' War packs, but you'll also have a pretty good chance of snagging extra rares and mythics! You can check out the full list of these retro artifacts over at Scryfall.
The good news doesn't end there, however, as Wizards of the Coast has also taken this opportunity to increase the amount of rares and mythics you receive when purchasing packs. Long story short, every ten The Brothers' War packs you purchase with either gold (free currency) or gems (paid currency) will grant you a Golden Pack which contains five random rares and one random mythic from the current Standard sets - all of which are duplicate protected! Needless to say, this is an absolutely massive improvement to MTG Arena's in-game economy!
And last, but definitely not least, The Brothers' War has brought with it a promo code that will grant you three packs for free. All you have to do is navigate to the in-game store, or the MTG Arena website if you're on mobile, and input the "PLAYBRO" code. Nice and simple!
Once the next big update goes live I'll make sure to let you know. Until then, have fun with all of the new stuff, and I'll leave you with the cinematic trailer: