Rex is the head engineer of the Miners, and he made nearly all the vehicles. Just before he was called to work with the Power Miners, he was working on a giant prototype Geo-thermal station, this could have later been the Underground Mining Station.
He has made it to the earth's core.
- The mechanic from World Racers (Extreme Daredevil's team) has the same face as Rex in 8864 Desert of Destruction set. This is a possible hint that the mechanic is him.
- Rex appears in LEGO Battles: Ninjago in three different stages, his original suit, a blue Mine Mech, and his silver miner suit.