Lao-Shan Lung, or "Lao" are gigantic Elder Dragons popularly believed to be the size of a mountain. This giant, slow moving creature would go in hibernation until it's necessary to leave the area.
In Monster Hunter, Laos could only be fought online. The extremely hard scales on its back develops from the Lao walking directly through mountains. According to the Monster Hunter Freedom 2 info magazine, Lao Shan grows as its body receives floating particles from the atmosphere. The red tint comes from the iron deposits near their environment; the blue tint comes from ash particles from the Volcanic Belt. This process takes an untold amount of time, suggesting that Lao-Shan Lungs have extremely long life-spans.
The Guild had to find hunters one day because of the approaching dragon heading for their town. It was later found out that the Lao-Shan Lung was running away from a Fatalis.
Lao can no longer be fought in the original Monster Hunter because it was online only, and the server shut down.
Lao-Shan Lung cannot be killed outside of Area 5. No matter how much damage is done, time will run out with the monster repelled instead of it dying.
The only exception to this is Frontier's Goushu version of Lao-Shan Lung, where it can be killed in any Area it is in.
The Lao-Shan Lung can be fought in the Guild after beating every 3* and 4* Quest (4* Quest: A Giant Dragon Invades!)
The Monster Hunter Freedom Unite G-rank Lao-Shan Lung is unlocked once all HR7 and HR8 Epic Hunting Quests are completed. Defeating it unlocks the G-rank Teostra, Lunastra, Chameleos and Kushala Daora.
In Monster Hunter Freedom Unite, the Village Elder gives a Lao-Shan Lung 6* Quest.
If timed correctly, the Dragonator can hit Lao-Shan twice causing double damage, but chances of this happening are very slim.
Use the Dragonator just as Lao-Shan Slams into the fort to use the double hit.
If beaten long enough and not yet slain, Lao-Shan will flee at 00:00 (Time up, happens often on other large monsters).
It's to be noted that the damage for the Lao-Shan Lung is not carried over from one fight to another so you have to kill it in one go.
It should be noted that if extensive damage is dealt to the Lao-Shan it will collapse for a few seconds before continuing onward to Area 5.
On Monster Hunter Frontier Online,HR100 Lao-Shan Lung gains deadly strength and speed. It can also be killed in any location.
Mentioned on MHF1 from the Female NPC with a basket on her head, that the Kokoto Village Chief slayed a Lao-Shan Lung all by himself.