This archetype wants to go wide and use some equipment to push damage, and Double Masters features some of the best Equipment there is
A 3/4 for three mana is potentially problematic for aggressive decks, at least in the right shell
I'm also running Tamiyo's Journal, which can give me a steady trickle of Clue tokens and Revel in Riches, which can give me Treasure tokens
This means that players can challenge an opposing character, banish it and challenge another in the same turn with this card making it a ruthless enemy
Costing seven mana is a lot, but reducing every opponent's creatures by -2/-2 and buffing your own by +2/+2 is a powerful ability
Like their metallic ink colour suggests, steel cards are built to be tough, with strength and willpower stats that are often higher than their counterparts in other ink colours