Mercer is a shrewd and ambitious businessman who saw the potential of Pandora. With his co-worker Alma Cortez, he created TAP in order to get easier access to Pandora's resources from the Na'vi without the financial expense of a prolonged conflict. He hoped to impress the RDA with Na'vi diplomats who were loyal to humanity
In 2138, Mercer along with Angela Harding and Alma Cortez kidnapped a group of Na'vi children from the Sarentu clan with the aim to train them to become cultural ambassadors. The kidnapping resulted in the decimation of the Sarentu, a deed which Mercer and Harding hid from the RDA by fabricating reports and destroying the bodies with toxic chemicals
Mercer will make his first appearance together with his right-hand woman Angela Harding where the two will enter the class of children in the TAP program and will try to train them. Some of the Na'vi children will try to attack Mercer and will be overwhelmed because they are still too young. Mercer will put he will risk the children or force them to do horrible things to transform them into his soldiers by brainwashing them, even in his first appearances it will be shown how he will be able to manipulate some children including the protagonist's sister who during an attack by a member of a tribe Na'vi will be killed by Angela and John in front of the eyes of the other Na'vi sister who will manage to escape thanks also to the help of the other Na'vi reached by Alma the protagonist will plan revenge against Mercer and Harding by first killing Angela and presumably then killing John after a fight in one of his compounds where he will be crushed by a robotic arm and will be left inside the compound during the explosion
