So there isn't a gimme introductory boss, especially with a two boss raid. I would say the first of the two bosses is somewhere around the range of a mid to late tier Battle of Dazar'alor encounter, think like a Rastakhan or Mekkatorque. And then the final is boss is hard. It's end boss level, like a Jaina. Not necessarily harder than Jaina, but comparable to Jaina in challenge.