Her two abilities are Trance which lets you send the top two cards from your deck to the graveyard (called milling) and in return, Terra gains Flying, making her much more difficult to block
On paper this looks like a two to four mana investment for something that doesn't even ramp you for following turns unless you didn't otherwise have lands to make
Product Details Trance At the beginning of combat on your turn, mill two cards
You just have to hope that nobody else casts a world enchantment of their own to get rid of it
Perhaps the best way to keep an odd number of cards in hand are abilities that let you draw
But even treating this as a 4-mana 3/2 that draws you a card sounds really good, and you can obviously divide up when you cast the two halves to make it feel even better and if you always have the mana available when it dies, it will just keep coming back When it has a big enough friend around, it is going to be an intimidating attacker on any board and that alone is enough for the Ruiner to be relevant almost all game long