Riven, the Exile

Fighter (Whenever this creature attacks, you may
have it fight target creature you don't control.)
{1}: Riven gains first strike until the end of turn.
{1}{r/g}: Riven gets +1/+0 until the end of turn.
{1}{r/g}: Riven gets +0/+1 until the end of turn.
"What is broken can be reforged."