Several western European countries recently experienced the establishment of more than one populist actor in their party system. While we know how populists attack the political mainstream, we lack knowledge on how populists talk about other populist actors. Conducting content analysis of campaigning communication on Twitter and 23 interviews with populist MPs in Germany, Italy and Spain–countries characterised by the presence of various populisms–we find that populists demonise each other perceiving themselves as adversaries. Populists attribute a malicious and extremist character to the (populist) opponent when the latter is ideologically distant indicating the decisive role of host ideologies. Positive evaluations only occur by overlapping policy position. Some specificities emerge in Italy, where established populists behave more like the mainstream. Being populist as such does not unify political actors in the fight against the establishment: populists appear at least as hostile towards other anti-establishment parties as towards the mainstream.