Nahkriin

Nahkriin is one of the eight Dragon Priests found in The Elder Scrolls V: Skyrim. His name means "Vengeance" in dragon language.

Interactions
Nahkriin can be encountered within the Nordic ruin of Skuldafn during the main quest The World-Eater's Eyrie. He must be defeated in order to obtain the Dragon Priest Staff which is used to open a portal to Sovngarde. However, it is possible to access Sovngarde without fighting Nahkriin, by simply sprinting past him before he closes the portal. But, naturally, you cannot obtain the mask Nahkriin from his body.

Nahkriin knows spells from every school of Destruction, can summon a Storm Atronach, and wields the Dragon Priest Staff - however, he favors Icy Spear and Incinerate.

Notable items
Upon his defeat, Nahkriin drops the Nahkriin Mask - one of the eight mysterious Dragon Masks located throughout Skyrim. This is the only opportunity to obtain this mask as it is impossible to return to Skuldafn.

Collecting all eight masks is a requirement for the unmarked quest to restore the Dragon Priest Shrine. Once restored, the ninth mask (Konahrik) will be accessible by the player.

Trivia

 * He is one of two Dragon Priests that does not exit from a sarcophagus, the other being Morokei.
 * While in combat, Nahkriin will speak in Dragon Tongue. Aside from Morokei, he is the only Dragon Priest that ever speaks to the Dragonborn.