Fan Casting What Remains (sci fi fantasy epic)

Several years ago a colony of humans crash landed on a planet that is populated by giant humanoid aliens. Over the year humans become nothing more that pests to these giants and spend most of their time running from being killed. Zev is a young man that goes against the wishes of his tribe to go rescue his love Mora, who has been taken to their city. When he arrives there he comes to realize that the planet used to be inhabited by other human sized beings that worshiped the giants as Gods, then the giants turned on them and now all that remains are ruins that he uses to hide and evade the giants. Eventually he manages to kill a few giants and rescue his girl. When he returns he convinces his tribe to work together to defeat the giants once and for all.