From 1936 to 1938, the Austrofascist Ständestaat and the Nazi German Third Reich increasingly quarreled over the question of unification. Paradoxically, Austrofascists founded their arguments for autonomy from Germany by claiming Austrians were Germans, albeit of a regional variety: southeastern, Catholic, and Alpine as opposed to northern, Protestant, and Prussian. Austrian right-wingers founded their own German nationalism on competing regional identities, a constitutive contradiction that brought together right-wing agents across the Austro-Bavarian border into fraternal solidarity. But it also instigated fratricidal violence over the "right" way to be German. The result was a perception of two German brother peoples living in two German states, each with an Austrian-born leader. This article traces how, from 1936 until the annexation, these regimes engaged with each other in two senses of the verb: as opponents in a Bruderkampf and as friends in fascist Germanic cooperation. They even embarked on official joint projects of ethnonationalism amid an unofficial war, resulting in an intra-national borderland as chaotic as any international space in twentieth-century Europe.