Because every Retail WoW story goes like this:
Bad guy: This...is your...END
*Dark orchestral music
Good guys: No...this is...our HOPE
*Swelling hopeful orchestral music*
Bad guy: All according...to my PLAN
*vanishes in a cloud of smoke or dies*
Good guys: We heckin' did it
*Looks smugly at the camera*
*More swelling hopeful orchestrals*
Other good guy:....for now....
*Everyone gives a resolved expression*