Meet End-Of-Days, a firebird dragon who spends most of its time wreaking havoc on human settlements. End-Of-Days has an agreement with another dragon, Lithodux, where Days collects treasure and Lithodux hoards it away.
End-Of-Days is so named because the trail of smoke left in its wake is so thick that is smothers the sun, as well as the dragon's incredible ability to destroy human kingdoms. When End-Of-Days is spotted on the horizon, the humans will cry, "The end of days is coming!"