Winged Steed of the Ebon Blade

Dead or alive, you're coming with me.

Riding Requirements:

This mount is available to all eligible characters on your account.
Level 10
Apprentice Riding (ground)
Expert Riding (flying)
Death Knights only

Source:

Dread Commander Thalanor in Eastern Plaguelands.
Cost: 1000

Notes:

Although other classes can reach this vendor, only Death Knights can purchase the mount. One learned, it can be used by any Death Knights on your account, but no other classes.

Introduced in:

Patch 3.0

Travel Mode:

Ground (+60% or +100% speed)
Flying (+150%, +280% or +310% speed)

Speed depends on your riding skill.

More info on Wowhead:

Winged Steed of the Ebon Blade taught by Winged Steed of the Ebon Blade