As Genesis describes beginnings, so does Revelation describe a consummation, an end. Revelation, like the entire canon of sixty-six books, describes God's continuing mercy in face of a relentless judgment.
Salvation is extended universally to humankind.
Revelation is an apocalyptic literature describing a vision insufficiently captured in myth, symbol, and image. Revelation is a Christian book written for Christians, but its poetry is epic. Revelation was never intended to be read as an almanac of historical events. The entire sweep of history is under God's control, and God will in the End triumph over all ungodliness. No power within history is capable of winning the final victory over evil 10.