United in Stormwind Cards List & Guide
Passive Hero PowerYour hero is Immune while the staff charges.
It is acquired by beating every wing of the league of explorers in HEROIC MODE!!!!!
It is not, that's a boss' hero power.
Patch notes say that you get it by completed in Heroic mode
The heroic mode card back is called staff of origination..
Second boss, first wing.
Nope, I was wrong. Will update with verified infos.