Aurora Glade (mission)

This is one of the more challenging missions in the game, and I suspect difficult if not impossible to finish with henchies or people who cannot follow instructions and work as a team. At the end of the first portion, you must race against the White Mantle who are attempting to activate the druid portals, and have far superior numbers. You need to find and slaughter the White Mantle crystal carriers as quickly as possible, all the while sending your own crystal carriers to also activate the portals.

Preparation

Since you need to move fast as well as slow the Mantle runners, Warriors should equip skills like Sprint and Hamstring. Mesmers, bring along your Imagined Burden or Ethereal Burden (whichever lasts longer based on your skill specializations).

Also, there are a lot of level 20 named mobs of varying classes, so equiping capture signets is worthwhile. I have not seen or heard of anyone capturing any elite skills here however.

Mission

The mission begins with an easy but long run through the jungle. When you start to reach larger groups of White Mantle be sure to hit the Abbotts first. Activate the first portal to clear the vines blocking the path. Fight on until you get to a spot with two portals, at left and right. This is just after the bonus activation (see below). To open the way forward, both portals need to be activated with crystals. These can be obtained from the druid at the bottom end of the glade. Doing this starts the White Mantle running to activate the portals, so make sure you have your tactics discussed first. If you see someone running to place crystals and you are uncertain that they understand the nature of the mission, wait at the druid for the second crystal to pop after they place the first, then grab it. Now you have control of the timing.

A tactic that was effective was to split the group into two groups of three. The crystals that you need to charge the portals are obtained right at the entrance from the druid there. Have three players that are not going to go White Mantle runner hunting wait there. The first player runs the first crytal, and as soon as it is placed another will appear for the next waiting player to immediately grab it and start running it. Portals that glow blue are yours, red belong to the mantle, and white are unclaimed. It is probably best to head for red portals first. After placement of their crystal players can join the fight against the mantle runners, but it is good insurance to have at least one return to the druid in case the Mantle sneak a runner past you and steal a portal from you.

One tactic that worked was to let the Mantle claim all bar one portal. The last one they try to claim is the one directly opposite where they appear from. To get here they have to go between two cliff areas and then across a land bridge, providing two natural choke points where it is easy to kill the runners with their crystals. Place the majority of the group between the two cliffs and another one or two back in the second in case the crystal runner gets through the former. Often you can block the runner with your character's body. Once you have done this, just slay all White Mantle that come out. When no more come, the bonus mission is trivial as is claiming all the portals.

After the portals are claimed, a cut scene plays and you are transported into the hedge where you need to kill the Hedge Guardian, a level 20 Behemoth. It's an easy fight, after which another cut scene plays and you will find yourself at the Henge of Denravi.

From there you get a quest to follow a spider (who soon dies), but who would have led you to a boatman. Give the boatman the correct answers, and when you are ready he will take you to Riverside Province where the next mission is available.

Bonus
Rescue the ranger with the odd name from White Mantle attacking him. He will tell you of the Demagogue, a powerful member of the Mantle whom you should kill.

When you get to the final crystal stage (where you have to convert the 3 portals while the Mantle also send runners to do the same), the Demagogue is positioned near where all the Mantle are coming from. I think the best way of doing this is to kill all the Mantle's runners and drive your way to where the Mantle are coming from, which means you shouldn't activate all the portals until you are done. You will need to be extra vigilant in ensuring that all the Mantle runners are dead.