We have a winner! It is day 12 and DREAM Paragon show their class and claim world-first Heroic Lei Shen. Congrats to them! Lei Shen is the last of the standard heroic bosses, leaving only "bonus boss" Ra-den. Ra-den has a 30 attempt limit per week and kills can be tracked here.
The kill was done in 10 man mode, with the following raid line-up: