Who is Soldier from Sarah Kane: Complete Plays and what is their importance?

The soldier is an Eastern European militant besieging the city of Leeds at the beginning of "Blasted". After the insurgents take Leeds, the soldier storms Cate and Ian's hotel room. The soldier devours the food and gin in the room, but a mortar round destroys it and nearly kills both Ian and the soldier. The soldier talks to Ian about the atrocities he has committed, including torture and rape. He talks about his beloved Col, who was raped and murdered by government forces. The soldier rapes Ian; then he pushes the barrel of a revolver up Ian's anus and threatens to shoot. Soon thereafter, the soldier commits suicide.