Christ took the form of a human and underwent human death, in a thematic response to the fall of the first human as recounted in the Bible's creation story. Nei

Christ took the form of a human and underwent human death, in a thematic response to the fall of the first human as recounted in the Bible's creation story. Neither Genesis nor the Gospels are to be read as complete lab notebooks of creation and redemption in sufficient detail to allow others to replicate it. They are stories of the relationship between God and humanity. If there are other human-level-intelligent species, there are a number of possibilities, including that they had their own messiah that took their form to fix whatever they'd screwed up, that they had the very same messiah, or that they didn't need one in the first place. It's possible that they don't die, in which case it wouldn't really make sense to apply Christ's redemption to them - but we still die, and so the concept of Christ defeating death by his own death does not become any less applicable to us. (As another commenter mentioned - C. S. Lewis's Space Trilogy explores the idea that only humanity fell, and intelligent life on the other planets knows God but didn't need the redemption of Christ.)