Meridia

This small village is located in the center of The Vale of Twilight, entered via a portal from the south side. It is a small area with numerous NPCs, including:
 * mailbox
 * auctioneer
 * general vendor
 * potion vendor
 * hireling vendor (Levels 14-16)
 * farshifter Bazbeaux (to The Twelve)
 * tavern (The Windswept Oasis)

The tavern is not the collection of tables at the entry (which is the potion shop), it is on top of the central temple, which can be accessed via the ramp on the north side of the temple.

Accessing Meridia
You may receive mail from Valairea Satnarine directing you to go to Meridia.

Meridia can be accessed within the Vale of Twilight. The gate there is found at the top of a stone ramp which starts from midway on the path behind the tower of The Twelve (run either way, about the same).

However, if you go without first speaking to Gustavine Kyerrh in the Tower, you will get the message: "The powerful magics of Gustavine Kyerrh block your access to the Vale of Twilight. Seek him out within The Twelve."

Speak to Gustavine Kyerrh (found in the southeast corner of the Tower of The Twelve), and get the simple quest "Meridia". The gate at the top of the stone ramp, leading to the wilderness area of the Vale of Twilight, is now open to you.

The monsters in the Vale of Twilight are around CR 15 or so, so fight or avoid as you prefer (Invisibility seems to work well for most here). Follow the path, bear right at the first split, heading under the stone aquaduct and over the small bridge. The walls of Meridia are now on your left. The path winds a bit; take the next left, keeping the walls of Meridia on your left, and follow that to a magically supported stone arch, and a final left to the entry to Meridia itself.
 * Note - Rats, spiders and scorpions may be slow, but they will follow you to the gate itself. Do not consider yourself "safe" until you are inside.

The Teleport spell can take a character to Meridia, but only once they've finished the Meridia quest.

If your Guild Airship has a Farshifter among its amenities, characters can also reach Meridia via that, once they are sufficient level.

NPCs

 * Aaseamah Screven - Grandmaster of The Twelve. Receives the quest to find Meridia, and bestows The Thirteenth Eclipse (story arc)
 * Arahi - Scholar of the Planes (Portal Fragment Collector)
 * Bazbeaux - Keeper of the Shroud, farshifter to The Twelve
 * Bryonson Wintir - Eberron Energy Cell vendor
 * Harboni - Reforger of Blades (Blade Storm Fragment Collector)
 * Helema - Holistic Practitioner (Healing Totem Collector)
 * Kyrian Flamewarden - Hireling Vendor (Heroic level 14-16 only!)
 * Marala - Bane of the Barbazu
 * Omerilda Helton - Banker
 * Shilhi - Artisan of Vitality
 * Thurstain Graylin - Healer
 * Valairea Satnarine - Eldritch Expert. Receives Eldritch Device Tutorial
 * Valrelyn Jenscena - Tavernkeep
 * Yarima Rickala - Auctioneer

Quests

 * The Vale of Twilight - Aaseamah Screven
 * To Curse the Sky - Liria d'Deneith
 * Creeping Death - Trull Knopper
 * The Shroud - (Raid) Aaseamah Screven
 * The Codex and the Shroud - (Raid) Rael Omastoro
 * Eldritch Device Tutorial - Valairea Satnarine

Zones

 * The Eldritch Chamber
 * The Vale of Twilight
 * The Shroud