The Oduduwa secessionist group is an ethnic separatist movement that seeks an independent nation for the Yoruba of southwest Nigeria. The group adopts a radical approach to secessionism and has conducted extensive online campaigns and activism on social media. Unfortunately, there appears to be insufficient linguistic research on discourses produced by this emerging group of activists. Hence, social media campaigns published by the Oduduwa secessionists have been selected to uncover various discourse-stylistic strategies at work from the standpoint of the socio-cognitive model of critical discourse analysis (CDA). While employing a mixed-method approach, this research analyses 500 samples purposively retrieved from Facebook and Twitter. The study reveals the ideological structures concealed in the rhetoric produced by members of the group. The secessionists construct a cognitive binary of positive self-presentation and negative other-representation, categorizing Nigerians as well as the President Muhammadu Buhari administration as the Other. The underlying motive is to reinvent an identity that is different from a typical Nigerian. Since the Oduduwa agitators are a group of individuals determined to secede from Nigeria, the structures of their campaign discourse reflect discourses that reinvent the group’s identity and elucidate their ideological stances. Expectedly, grammatical and discursive structures common to activist discourse, such as hate speech, name-calling, coinages, indexicality, and threatening language that portray prejudice and cultural divisiveness, are evident in discourses produced by the Oduduwa group. Oduduwa separatist movement, as the marginalized group, strongly enunciates their cultural ideology through these strategies, and in pursuit of their self-determination, they accentuate their belief and resistance ideology in ethnic difference and cultural distinctiveness.