Paarthurnax (Quest)

Paarthurnax is a Quest in The Elder Scrolls V: Skyrim.

Background
Delphine and Esbern have discovered that Paarthurnax was one of Alduin's chief allies during the ancient dragon war. They refuse to give anymore help until you kill Paarthurnax.

Overview

 * Prerequisite: N/A
 * Quest Giver: Esbern
 * Reward: Opens more quests to recruit Blades members.
 * Reputation Gain: N/A

Bugs
After beating the main quest Paarthurnax becomes unkillable (as killing Alduin removes the quest). However, some players have reported that attacking and killing him will complete the quest, even though it has dissappeared from the quest log. (Confirmed) However in some cases Paarthurnax will remain unkillable even after the quest has disappeared, preventing further progress along the Blades storyline.

On 360 and PS3 there is a glitch where Paarthurmax is unkillable; directly after recieving the quest. However this glitch allows you to level up your skills, if you wish to waste the time and arrows.