The merger introduced several pivotal characters to the main cast: Mercy West Medical Center | Grey's Anatomy Universe Wiki

Mercy West Medical Center was originally a rival teaching hospital to Seattle Grace, located on "the other side of town" in downtown Seattle . While Seattle Grace was often portrayed as a more prestigious, elite facility, Mercy West was characterized as a high-volume center specialized in trauma and known for its competitive environment—often referred to by fans and characters as the "era of the schoolyard" due to its rigorous, sometimes cutthroat, staffing systems .

: To distinguish themselves initially, the Mercy West staff continued to wear their signature orange scrubs, while Seattle Grace staff wore traditional blue. Key Characters from Mercy West