The Changbai Mountains were 2,691 meters above sea level (the highest peak in China, White Cloud Peak) and 2,749 meters above sea level (the highest peak in North Korea, White Head Peak).
One great 'The Mountain' fanfiction is 'The Mountain's Redemption'. It shows a different side of the character, exploring his past traumas that led to his brutal nature. Another interesting one is 'Mountain's Quest', where he embarks on a journey away from King's Landing, facing various challenges that force him to re - evaluate his loyalty.
In some cases, the Mountain might be paired with other powerful warriors from different regions in fanfiction. For example, a character from Essos who has a unique fighting style. This could lead to some epic battles and exchanges of combat techniques in the fanfiction.
The Changbai Mountain was 2691 meters above sea level. According to the information provided, the Changbai Mountain was ranked fifth among the famous mountains in China.