Kirito of the Mytheral Pebble

This creature gets +5/+5 if a Pebble is on the battlefield.
"For you see, long ago, this mighty weapon was forged in the fiery pits of Tartarus in a time before the world began... And thus, Mardoza, guardian of the pebble fell to his knees and passed from this world, leaving behind the mighty weapon, for he knew it's power would be acquired once more."