I've gotten 7 rares so far, and only got my first dupe at 7. It's all up to luck, someone else on my server's gotten 7 in a row being unique...so...yeah...

Onoki-Darui-Chojuro-Mifune-Danzo-Killer Bee-Onoki

also, the Killer Bee was pulled after a month worth of free pulls after Danzo, which is most likely due to the kage treasure rates getting all mixed up after 3.0.