This quest takes place at the Dragon Ring in Great Divide at -5, -344, 40 .
Several waves of Rime will attack, alternating sides. They will come in very fast and all be heroic. After a short time, an epic x2 named ettin will attack with a group of heroics. Once him and his group is dead this quest will automatically complete.
Gninja shared some more insight on how this event will play out:
The event has three stages. Stage 1: tokens spawn at fairly slow rate and low end heroic mobs spawn during the attacks. Stage 2: number of tokens spawning doubles and high end heroic encounters spawn during the attacks. Stage 3: Final epic encounter attacks and tokens again double. Once the epic encounter is defeated the event is considered complete but the tokens continue to spawn around the areas at stage 3 rate.
If you're not getting quest credit for the battle quests, not engaging in the named encounter is likely the issue:
The quest will only update if you actively engage the final named at the end of the event waves. That named is what stops the NPCs from keeping spawning. One thing I was seeing people do was standing near the spawn points where the creatures spawn and engaing and killing them very quickly this might leave some not getting update as they will not have an opportunity to get on the hate list.
This article refers to events, personae and activities that were introduced for the Velious Transportation Event. This event originally began at 12pm PDT on July 14, 2011. It was re-activated at 5:30pm PDT on July 22, 2011.
For each server it will run until the dragon ring and wizard spires are completed. Ground spawns and merchants will remain in-game until 11:59pm PDT on August 22, 2011.