The Core

You are "The Stranger". You have been teleported to a dystopian future where two factions are at war with each other,  an alien bug species called "The KruKru" and a robot faction called "The Sentinels". In the middle of this dreadful war is the last enclave of humanity. They were tasked to defend "The Core". If either of these factions got a hold of the Core it could mean the end of all life.