Legendary Dragon

The Legendary Dragon is found in. It is found randomly while walking around and fast traveling to towns just like other random dragon encounters. After it is defeated the player gets the "Legend" achievement/trophy. It can use the Dragon Shouts Frost Breath, Fire Breath, and Drain Vitality. His horns are similar to the one of Durnehviir but have only 2 horns while Durnehviir have 4.

Battle behavior
The Legendary dragon acts like any other dragon in combat. It attacks with its breath, and may sometimes land either on its own or if the Dragonborn uses Dragonrend. Also, this dragon, along with the Revered Dragon, uses the shout Drain Vitality on the player.

Trivia

 * It seems that there is a respawning legendary dragon at Mount Anthor, once the player reaches a certain level.
 * According to many experiences once you reach level 78 these dragons are very often found at the Dragon's Lairs.
 * A good way to find one, is to fast travel to every single Dragon Lairs. There are also a few places where some dragons will regulary spawn such as The College of Winterhold and Morthal.
 * They have the highest chance of appearing once you reach level 70.