Board Thread:Lore Discussion/@comment-14027812-20130901035234/@comment-7953253-20130901074058

Alduin might fear the Dragonborn, but that doesn't make him a coward. Being too afraid to fight the Dragonborn, is cowardly.

Alduin fled to Sovngarde to regain his strength after his defeat on the Throat of the World with the Dragonborn. He couldn't overpower the Dragonborn so he had to retreat, he's not gonna just stay there and die. He also fought the Dragonborn in Sovngarde once again when the Dovahkiin had followed him there.