Just wanna say a bit about Altruis since he's one of the coolest NElfs ever. :P

Altruis is of course, a demon hunter. Originally, he was allied with Illidan and actually went through the Dark Portal with him. He later defected after he began to realize that Illidan had become the very thing he was sworn to fight.

He wears the blindfold because, obviously, he has no eyes. All true demon hunters do not have eyes, as part of the initiation to become a demon hunter, they are ritualistically burned out. This gives the demon hunter the ability to detect demons and undead with unerring accuracy.

Anyway, cheers!