I have seen several people over the last few days inquire about the quest to enter T8. I decided to write a guide to what I have discovered so far.
SPOILER BEWARE......
Step 1 is to gain access to Dread Spire Keep. This is done by killing and hailing the faeries from CT, Xegony, and Phara Dar.
Step 2 is to kill Zi Thuuli, Red Fang, and The Bridge Keeper in T1 of DSK. Loot the 3 heads and turn them in to the T2 Access NPC at zone in.
Step 3 is to go to Messenger of Lord Drizku and hail him and go through his text. He will give you a series of tasks to complete.
(You need to loot the essences while having the task for them to count. If you fail the combines, you can get the Pure essence from other means i.e. guild bank, purchase from other, etc...)
The tasks start in Plane of Fire. You need to kill random mobs and loot the 3 essences of fire. Take them to a forge and combine them and create a Pure essence of Fire.
Next go to Sleepers tomb and farm the 3 water essences. Combine in a jewelers bag.
Next go to Kingdom of Wind and farm the 3 Air essences. Combine in a loom.
Next go to Plane of Fear and farm the 3 Earth essences. Combine in an oven.
Return to Messenger and turn in the 4 Pure Essences. Receive a letter to take to South Karana and hand in. The NPC spawns around the well (12 hour spawn). Talk to him and receive a stone to hand to the golem which when turned into him triggers the fight. Kill the mob that spawns and loot the Fragment of Mortality. Hand it in and welcome to T8 ( I think. Haven't beat the fight yet).
Someone may want to confirm this is the end.