History of Boss Bully

Boss Bully: "Defeat bosses in any activity" with a progress objective of 25 bosses.

How to complete

Any boss kill counts, so farm quick boss encounters such as Onslaught boss waves or Court of Blades challengers. The event-specific Rushdown activity from Guardian Games was also reported to count, but I could not open a source confirming that. Rewards and seal are unconfirmed.