Ancient accounts of extraterrestrial battles variously pitted light against darkness, order against chaos, pride toward one’s betters, power against power, or good against evil (not necessarily in modern terms). The notion that heavenly war hinged on the proposed creation of earth and the prospect of a deepened agency granted to its future human inhabitants was untaught until Joseph Smith’s revelations in the antebellum United States recast the war from cosmic military engagement to a clash of ideas concerning “salvation.” In Joseph Smith’s panorama of what existence is about, not even love, grace, intelligence, or relationships eclipse agency as prime values; their very nature and meaning depend on it. To inhibit agency is demonic. In what sense and by what means did Satan seek to extinguish this agency? The  additional questions spawned by examining assumptions and possibilities lay bare something of the nature of agency itself, along with threats to it. Whether to believers who take the War in Heaven as actual pre-earth trauma or to skeptics sensitive to the potency of mythos, exploring the story’s contours may affect our maps of historical, existential, and spiritual reality. Hence it may condition how we choose to live.