The Evolution of ShadowDawn:

Once upon a time, there were two gaming systems, 
**Earthdawn** 
and 
**Shadowrun**

Then, there was a campaign where every player had two characters:  

One in the Shadowrun system, set in 2060 Boston

One in the Earthdawn system, set in 4th Age Caer Camrish

But the players were lazy, and so coined some names.

*Earthrun?*

*Nah. That sounds weird*

*Brian's Campaign #547?*

*Nah. He'd kill us*

*ShadowDawn?*

*Hey, that sounds kinda cool!*

And it stuck.  Now, both universes run in heavily modified [GURPS].  Check out the [HouseRules]