The Devil's Mouth is a huge, mist-choked void in the Mountain Pass that separates the Valley of Peace from the bandit-infested wastelands of the Northern territories. The only way across is to cross the Thread of Hope, a thousand mile bridge that spans the great chasm. The anchor points of this very long bridge are built upon the stony spires that thrust up through the mist of the Devil's Mouth, more often called the "Fangs of Hell".
The threat of being plunged into the screaming void has deterred any attacks on the Valley since the bridge was built.
When Tai Lung escaped from prison and began his journey back to the Valley of Peace, the Furious Five took it upon themselves to defeat the snow leopard. After days of traveling, they eventually intercepted Tai Lung at the bridge looming above the Devil's Mouth.
When their attempt to stop Tai Lung by cutting the bridge ropes failed, Tigress ended up battling Tai Lung alone while her comrades held up the severed ropes. Tai Lung soon gained the upper hand, and Viper and Crane ended up charging forward to aid their friend. At one point, Tigress nearly fell to her death into the abyss, but was saved by Crane. They were soon joined by Monkey while Mantis struggled to hold up the bridge and its occupants by himself.
The Furious Five worked together to beat Tai Lung back, and eventually wrapped him up in one of the ropes and sent him tumbling down into the Devil's Mouth. Mantis pulled his friends back on the cliff side. Just when it seemed that they were victorious, Tai Lung swung back up on one of the ropes and landed behind the Five, taking them by surprise. Tai Lung then paralyzed them all with his nerve attack, leaving Crane to carry his friends back to the Jade Palace in order to strike fear into the hearts of the current residents.