Monster Hunter Alpha Dos DLC: Crumbling Crag

Monster Hunter Alpha Dos: Crumbling Crag is free DLC accessable from Eko Harbor via West. It's monsters are as difficult as monsters from the Hi difficulty setting (monsters half 50% more health and attack, 30 minute time limit, slightly better prizes, etc.) of the main game. The cover shows the Unknown Cloaked Elder Dragon, as he is the flagship of the DLC. The main city is  Sananthia City.

New Monsters
These monsters can be found on the main Alpha Dos page, but the ones exclusively found in this DLC are:

Bird Wyverns: Reversed Great Jakki, Acrid Great Devvi, Tropic Great Lokci, White Cuyudrome, Furkkuffu

Brute Wyverns: Apex Brachydios, Volt Dinovaldo, Diamond Pyraklorisk, Isumius

Flying Wyverns: Regal Rotiona, Regal Rogaia, Blackfish Spinozyca, Kuroikari, Zerureusu

Leviathans: Cadboros, Mantibo

Elder Dragons: Golden Harudomerugu, Jade Shantien, Unknown Cloaked Elder Dragon

Areas
Skeletal Forest: A forest with trees turned to stone over many years. The little water that is there is fought over by the inhabitants.

Moving Cave: A cave with lava that carries so much rock, it makes the ground seem to move. Lava drips from the volcanic vents scattered around the cave.

Battleship: A massive boat designed to trap monsters in a secure environment to be hunted. It's failures leave it held together by unstable rope, even though it's still used.

Crumbling Crag: A cliff that has a seemingly bottomless pit on one side, and the only entance/exit on the other. A beast that will not show it's body. He stays away from the edge, aware his weight could cause it to collapse. He makes a Tigrex look incredibly small.