Ender - INFJ.
Everything about the way he operates is based on a complete understanding of other people/entities, which leads to a heightened capacity to empathise with them, but also the knowledge of how to defeat them. He doesn't generate possibilities so much as answers, and he's absolutely person-focused rather than focused on impersonal things.
Also, the way he shifts his perception of directions screams Ni to me - I do that all the time, in non-null gravity.
So, definitely NiFe or FeNi, I think. I'd guess NiFe because he's more obviously N than he is F (he's at least somewhat balanced on T/F).