His father, Dr. Eric Chanikov was the scientist that developed the Sigma Technology, after its appearance. His mother died in 1908, exposed to the blast of the explosion caused on the Tunguska Event caused by the test of the "Death Ray" of Nikola Tesla. When the explosion ocurred, he was also exposed to the blast, but he luckly survives adquiring extrahuman abilities due to his combination with the Sigma Technology as a result of his exposure.
Rex doesn't remember much about his youth. After his incident and without knowing about his accident, Rex is sent to America with a trusted companion of his father, while his father goes into voluntary exile to the Variatas Archipelago. He spent his life exploring a lot of places in the world as the wilds of Africa, the ice shelves of Antartica, and the sultry jungles of the Amazon as an adventurer he is. He also worked as a war correspondent doing a cover in the Spanish Civil War. Some facists attacked the village he was in and he risked his live to save a wounded soldier, breaking the first rule for journalist: you don't interfere. For that reason he was fired after he return to the United States.
Rex lost contact with his father when he was a baby. The only way Rex could know about him was by cutting newspaper articles, discovering in the process his reports of the Sigma Technology. Believing his father was dead for several, Rex recieve a letter from him asking to visit him. This change all the perspective Rex had of his surrounding happenings.
Searching for his fatherEdit
His father told him about his whereabouts and regarded about some "truth" that must be told. The petition had an urgent matter, because for his father, it was getting too late.
Upton Julius' betrayalEdit
Rex go to look for his father to the place where he was told. The place resulted in being a lab. He enters the lab, but discovers no signs of his father. Instead, he discovers a frozen Tigging Mantis. Suddenly, he is surrounded by Upton Julius's creatures which force him to exit tha lab breaking a window. He temporaly manage to escape, but many creatures surround him. On that moment, Julius introduces himself and undirectly lets him know he came there to capture him. Rex start fighting with the creatures, but appears to be outnumbered. Then, Lucy Willing arrives on a flying train and start shooting the creatures helping Rex to get aboard the train and escape.
Meeting Lucy WillingEdit
Rex meets Lucy while rescued from being captured by Upton Julius. She took him on his train to a nearby island where she introduced herself as Dr. Chanikov's friend and co-worker. Rex asked her about his father's fate, to which she explained him that his father was taken by Upton Julius and that she is also being chased by Julius ever since that happened. She also stated that she doesn't know the reasons, but that it started after his father sent a letter to him.
Whitey Hooten's ConfrontationEdit
After Rex arrives for the second time to Isla Undisonus with Lucy this time, he is told by a villager that he was no longer seen on the island since two men came for him. So he goes to his father's lab to look for him, but he only finds Neuro Toxin darts, which he though his father were keeping for protection against the creatures. After fighting Whitey Hooten's army, he ask Whitey on the radio about his father location. Hooten, laughing, tells him that his father is dead and is buried nearby. On that moment, Rex concern of happenings in the chain grew as his courage for stopping Upton Julius and his men, starting from Whitey Hooten. Soon, Rex and Lucy go to defeat Whitey once and for all to Isla Glacialis.
During his fight against Upton Julius. Rex realizes that the Sigma Technology is too dangerous to be handled. That is why he convices Lucy that once they defeat Julius, they will destroy all remains of the Sigma Technology. This end up to be ironic, due to the fact that Rex itself is a product of the Sigma Technology, and survives at the end of the Campaign.
He is seen wearing a brown vest and a white shirt under with brown pants and boots. He always carries his rifle on the back since Lucy gave it to him. He doesn't fight with another way than shooting his Neuro Toxin darts at creatures. If surrounded, the best way to defend is to use his garrison function.
Rex exposure to the the Sigma Technology and adquisition of his unique abilities, encouraged Upton Julius interest on him. The main goal of Julius was to capture him so he could use him in his world conquest plan. At the end of the Campaign, Rex eyes turn white, sign of becoming fusioned with creatures. Rex abilities consist in a mixture of animals's: