The second band to use an umlaut in its name was the Krautrock band Amon Düül, which later split into competing Amon Düül and Amon Düül II factions. Amon Düül originally formed from a radical West German commune that also included future members of what European terrorist group founded in 1970?
the Red Army Faction (aka Red Army Fraction aka Rote Armee Fraktion aka Baader-Meinhof Gang)