Only two weeks after 
Tomb Raider: Underworld's 
first DLC (
Beneath the Ashes) hit the Xbox Live Marketplace, Eidos is now releasing 
Lara's Shadow.  For 800 Microsoft Points you can play as the Doppleganger:  faster, shadow-ier, and with devastatingly accurate and quicker attacks.  This DLC shifts Lara Croft into a more combat-angry stance.