There are two new raid zones coming to Norrath with Halas Reborn later this month! We've already shown you Underfoot Depths. The other new raid zone is Icy Keep: Retribution. Carlos "Gninja" Mora designed this zone with help from Cyndi "Xadrian" Johnson.

From Gninja:

What level is Icy Keep: Retribution and what size raid is meant to tackle it?

Icy Keep: Retribution is aimed at adventurers at or near the level cap of 90. It is a four group raid zone.
 
Which raid zones are of a comparable difficulty?

The difficulty should be aimed at the same difficulty as Lair of the Dragon Queen or slightly tougher in the later areas.
 
How many named mobs are there?

There are ten normal encounters and one challenge mode encounter. However some encounters might have to be unlocked in order to gain access to them through the questlines or various puzzles in the zone.
 
What's the lockout timer and about how long should the zone take to run?

I would venture to say most groups attempting the zone will not get all the way through it first time unless they are already taking the hardest stuff in the game but once they know what to expect from each fight it can be done in a few hours. The lockout timer is currently set to 3 day 20 hour minimum and a 9 day maximum.
 
What is the background story for the Icy Keep and who is E'ci?

E'ci is the goddess of the physical form of water. i.e. Ice. She is a third of the Triumvirate of Water with Povar and Tarew Marr. It is her minions who control the ice dragon egg and have watched over it. They have dubbed themselves Maidens of E'ci.
The upcoming Icy Keep: Retribution instance revisits the frozen dungeon of the Maidens of E'ci which has been featured during past Frostfell events. If you recall from the newest quest, An Exalting Experience, which was introduced last December had players heading back into the Icy Keep to further investigate the goings on of the newly hatched dragon, Vrewwx.
In Icy Keep: Retribution, players will head back into the zone once again to assist the Frostfoot clan with gaining entry into the main part of the Keep. The Frostfoots are fearful of possible enslavement once again now that that it has been confirmed another ice dragon, Vrewwx has been hatched. In attempts to preserve their way of life and avoid enslavement, the Frostfoot has recruited many goblins on their mission to find and slay the dragon.
The Frostfoots have assembled several different units on their mission to breach the castle. The units include the rammers, flingers and sneakies. The rammer unit enslaves native yeti's for their brute force to attempt to bash open the frozen doors. The flinger unit utilizes a catapult to launch Frostfoots over the castle walls to in attempts to gain entry. And lastly, Sneakies are a group of scout like Frostfoots that have taken to the underground tunnels to seek ways in which to open the magically sealed courtyard door. After several failed attempts trying to breach the Keep, the Frostfoots have become desperate and have decided to recruit outsiders with the promise of coin and a share in the spoils.
Players will assist Bartie Frostfoot in finding the new location of the baby dragon Vrewwx and also the whereabouts of the two sneakies that have yet to return after they were sent down into the underground tunnels below to find a way to open or by-pass the courty 
What's your favorite part of the zone?ard door.

That's a tough question. But if I had to choose it would be a tie between the Chessboard room where players have to defeat one of the named encounters in finishing off a game of chess and the Last room where you confront Vrewwx in battle.
 
What do you think is the most impressive part of the zone?

The Chessboard by far is the most impressive. The art team did a fantastic job really capturing what I was going for in there.
 
From Cyndi "Xadrian" Johnson:

What was it like being an apprentice for EQII and working on Icy Keep: Retribution?

Working on the Icy Keep: Retribution zone was both challenging and a lot of fun. As a budding apprentice I am always learning how to implement new things and the quests for this zone were a bit more involved than my previous quests based in Tenebrous Tangle. I think the quests turned out fairly well and I really hope the players will enjoy them. My favorite part of designing the zone was writing the dialogue for the quests. The NPCs have amusing dialog along with some interesting interactions.