Nirnian Dragons, or Dovah, are Dragons from the planet of Nirn. These Dragons are immortal (in the sense that they do not age and are very difficult (but not impossible) to truly kill). They take the form of large reptilian creatures with long tails, long necks, narrow horned heads, a single set of therapod-like legs, and a set of bat-like wings. They are deeply connected with the flow of time and can, therefore, sense users of Time Elemental Power.
Most Nirnian Dragons follow the leadership of Alduin, the supposed firstborn son of Nirnian Deity Akatosh, and aid the Shadow Alliance, but some, most famously Paarthurnax and Odahviing, have joined the Coalition.
Nirnian Dragons also speak in their own language (but are perfectly capable of speaking English), and their voices are so powerful, depending on the words the dragon says and whether the dragon tries to use its voice for this, the dragon's voice can produce various effects and attacks.
IE: The Dragon Words 'Yol', 'Toor', and 'Shul', meaning 'Fire', 'Inferno', and 'Sun' respectively, if said in sequence, will produce the famous Dragon Fire Breath.
Because of this, it is commonly said, "There is no difference between debate and combat between Dragons."