The Flag itself, representing the stars (members) of the Nationalists
The Nationalist Alliance, also known as the Nationalists and Reactionaries, is an loosely based alliance of Resistances, Insurgencies, Revolutionaries and Anti-Federalist that was formed as a means to fight the Multiversial Federation during the Nationalist Wars. It was dissolved after it's leader, who's reveled to be the Cruel Lord, ordered High Lord Aeon Thanotos to wipe out the Nationalist Defense Council, but remnants of it survived and where lead by various warlords, these remnants became known as the Nationalist Enclave and did not officially dissolved until the middle of the Third Multiverse War
History
the nationalist alliance was formed during the birth of multiversal federation and announce to unite the multiverses however that backfire because many political parties,nations and leaders decree with that and so nationalist alliance has been born and started wars with both multiversal federation and hegemony alliance