Battle for Siren's Call
The Battle for Siren's Call is a zone event in Siren's Call. It allows players to influence the outcome of massive NPC battles to control the zone for either the hero or villain side.
Copied and modified from PvP Zone Guide (Internet Archive Record)
When entering Siren's, the nav bar shows the status of the two zone minigames. The Battle for Siren's Call status is shown by the red and blue Score bar, and the Siren's Call Control currently displayed, either Heroes or Villains.
At any given time, the zone is controlled by either the Heroes or the Villains. When controlled by the Heroes, you can buy temp powers from the Hero Merchant just outside the hospital. (See Section 3.2.4 below.)
Zone control shifts back and forth based on battles at Siren's Call hotspots. At any given time, there are usually one or two active hotspots on the map, shown by white rings with red rays. Large groups of NPCs (armies) stand around there, and sometimes decide to shoot at one another; at the southeastern (waterfront) and northwestern (plaza) hotspots, they will wait indefinitely for players to get things started by creating aggro. Players can both attack enemy forces and assist friendlies with heals, buffs and taunts.
Neutral mobs also hang around the hotspots; they will aggro on Arachnos, Longbow or any player.
Once started, a winner will eventually be declared for the battle with a yellow zone-wide announcement. The loser is the first side to have X of their NPCs defeated, where X is something like 20-40. The defeats of enemies that con purple to players contribute a larger amount to the other side's victory. Thus it's possible to win a battle in which your side's army never fires a shot; neutral kills of your enemy will also help you win. The win will color the Score bar more blue (Hero win) or red (Villain win). When the bar is all red or all blue, that side wins zone control, which may unlock temp powers - see Section 3.2.4. The Score bar is then reset to 50/50 control.
(Note that if your side already has complete control of Siren's Call (i.e., unlocked all 9 temp powers) winning zone control will actually make it *easier* for the enemy to recapture the zone by moving the bar from 99.9% friendly control to 50%, with *no* benefit save the lousy 100 bounty if you're at the hotspot! Perhaps not what you'd expect for such an achievement.)