Their opponents committed atrocities such as the slaughter of civilians spectating a soccer game while fighting this group not based in Russia that partially caused a Bloody Sunday.
The Twelve Apostles were a special operations arm of this group and once targeted the Cairo Gang. This group burned the Custom House with heavy casualties in an attempt to destabilize their enemy's administration. Their opponents committed atrocities such as the slaughter of civilians spectating a soccer game while fighting this group not based in Russia that partially caused a Bloody Sunday. They fought the (*) Blacks and Tans and Roger Casement supplied the weapons for the uprising that eventually resulted in Michael Collins leading this group. They achieved peace with their primary foe in 1922 and earlier became the military arm of the organization formed following the Easter Uprising, Sinn Féin. For 10 points, name this army that fought the British for independence of a nearby Gaelic island.
The Twelve Apostles were a special operations arm of this group and once targeted the Cairo Gang.
Irish Republican Army [accept Sinn Féin before mention, prompt after; accept anything involving Ireland or Irish and Volunteers]