Once the Na'vi campaign has been beaten this trophy will unlock.
The final zone is similiar to the RDA version except you will be fighting off some RDA commanders. Make use of your skills especially health restore and titan bash to stun your enemies. Use dual blades for quick attacks. Once the two commanders are dead you will ride a Leonopteryx and defend the village for 3 minutes. Once this is done you will have completed the Na'vi campaign.