Théophile Jeusset (1910 in Rennes – 1968 in Nantes) was a Breton nationalist writer and fascist political activist. He is also known by his Breton language pseudonym Jean-Yves Keraudren. Born in Rennes on 25 April 1910, Jeusset adopted militant Breton nationalism from his youth. Initially associated with the Breton Autonomist Party, Jeusset broke away from it to form the fascistic Breiz da Zont movement and its political wing, the Parti nationaliste intégral breton (Breton Integral Nationalist Party: PNIB). The party was, however, tiny. Jeusset later joined with fellow nationalist extremists Gwilherm Berthou and Célestin Lainé to found Kentoc'h Mervel (Sooner Death), a group dedicated to direct action. Lainé, however, insisted that a more tightly organized group was necessary, going on to