Fifth Column/Council War 2005
Shortly before the release of Issue 3 in January 2005, this invasion saw forces of the 5th Column and The Council fighting on the streets of all the zones in Paragon City. This was part of the introduction of The Council, and in turn the removal of the 5th Column, as part of the storyline of Issue 3, which saw a coup d'etat remove Requiem as the leader of the group. This fed directly into the introduction of Striga Isle and the larger Council mythology.
The mechanism for the "war" was a GM or automated spawn of between 5 and 50 5th Column and Council troopers from minion to boss. These would con at the average level of the neighbourhood that the spawn was happenning (e.g. Level 6 in Argosy Industrial Park in Atlas Park). The number of troopers appeared to be based on the number of people in that neighbourhood - the more players, the larger the spawn.
The spawn would fight normally - 5th Column attacking Council if no players were around, both factions attacking players if they were. To prevent over-running of the zone, the spawn would not be triggered again until all enemies from it were defeated, and a short period (~1-3 minutes) elapsed. Considerable "farming" of these spawns was conducted by players, as a large number of average level, tightly packed foes presented too attractive a target to ignore.