Board Thread:Lore Discussion/@comment-24098614-20150903093108/@comment-70.83.46.99-20160125185726

On PC, you can also simply set the quest to complete and become part of the Blades without betraying Paarthurnax. This can be easily justified as your character "lying" to the Blades about killing the venerable dragon.

There's really no way for the Blades to know that you lied, either. Paarthurnax spends all his time meditating at the Throat of the World anyways, and the only way up there is fraught with a constant blizzard that can kill a man in seconds. Only someone with the Clear Skies shout stands any chance of reaching Paarthurnax.