The Wall

The Wall enters the battlefield tapped.
All Human creatures you control gain +0/+2.
{t}: Add {2} to your mana pool.
{3}{g}{g},{t}: Prevent all damage from any source
that would be dealt to you or your permanents
until end of turn. Draw a card.
Winter is coming, and with it the white walkers.
The Wall is where we stop them. The Wall was made
to stop them ... but the Wall must be manned.