Rex is a character in Lego Dragon Army
Rex has a Red a Ninja helmet like those on the later Ninjago sets. He has Gold Armour and a Red Ninja Suit with a Transperent red arm.
Rex's Dragon is a Brick built dragon that resembles a Red T-Rex with wings.
Before he joined the Dragon Army, Rex was a Fighter in a Ninja suit under the Alias of "The Flamethrower". He Joined the dragon army when his arm was sliced off.