MasterMargie

Guilty Gear X2 - I-no WTF, she doesn't die. Ever. On top of that, her special (which only the CPU can use) interrupts any combo you have her in, and she can take half your life bar in two hits. Also, props to Zophar from Lunar 2. It took me like a week straight of attempts to finally take him out. I'm pretty sure that's more time I've ever spent on a boss from an RPG. (period)