James Connolly founded his own Irish militia (the Irish Citizen Army) who were like the IRA but far more direct and much further on the left.

If I'm not mistaken, this "Red Army" was one of the first of its kind in the world; it was founded in 1913, following mass strikes in Dublin. Connolly was such a popular man that the wider Irish revolutionary movement had to absorb him+the ICA or else they worried that they'd end up launching a revolution without them. Connolly was executed for his role in 1916 but is extremely revered all over Ireland.