Rexicus Saturnus, better known as Rex, is a trueborn Mogadorian commander that served in the New Mexico Government Base in Dulce. He is involved in the operation led by Ivanick Shu-Ra to apprehend Adamus Sutekh at the end of The Search For Sam. He would later return in Hunt for the Garde as a narrator.
The Forgotten Ones
After Adam causes an explosion near the armory, Rex is the only suvivor but is trapped and seriously injured, but is pulled out from the rubble and nursed back to health by Adam. At first, he was hostile with Adam seeing that he is a traitor of the Mogadorian cause but seems to cooperate with Adam as they progress towards the Plum Island. This is a demonstration that not all Mogadorians, especially the true-born ones are not naturally agressive and ruthless. However, as Adam was about to escape with the Chimærae Rex noted that this will be the last time that they will converse as allies. Hinting that no matter there is a certain kindness in his heart, he still cannot defect in their race's cause.
Hunt for the Garde
After returning the Mogadorians, he is stationed on the Delta warship in Toronto and he programs flight directions for the ship. When the conditions of Setrákus Ra are unknown, the Delta's captain Jax-Har makes a move that could be thought of as treason to the Mogs, he decides to go check out Niagara Falls in hope of finding a Loralite stone. Mirra sees this as an act of treason and asks Rexicus to help her take over the ship from the captain. When she makes her move Rexicus does nothing and he then realizes he must get off the ship very soon and try to find Adam. He knows that the Mogadorian cause is wrong and he does not want to be a part of it anymore. The story ends with him making a plan to get off the warship. Then, at his ship, Phiri Dun-Ra gets in contact with the captain but is suddenly interrupted by Adam. Rex hears what he's saying and he's completely amazed by whatever Adam said.
United As One
He shows up when the Garde and its allies were about to attack the base in West Virginia. Adam then speaks up and says that he is not a threat and that he can help the Garde to get to the base and destroy it. He then becomes the navigator navigating the Loric ship to bomb and attack the West Virginia Base. He doesn't really have a great relation with Nine because Nine sees him like another evil Mogadorian. After the whole year that has just passed, he is found by John when he gives them a handmade symbol that he tried to make from the markings that he found in the Himalayas.