IAHGames added a new event... and didn't bother to include a list of reward in their post. Complete any Bounty Hunter's Guild mission (except for Demonic Sphinx, Minotauros, and Medusa) and get 1-3 Hunting Event Tokens from Event NPC. You can then trade them for various items in Bounty Hunter's Guild.
This seems somewhat similar to American server's Bounty Hunter's Guild Event in 2013, where you need to complete 500 missions for Cadet Elisa Character Card.
American server also added the same event, but with different prizes... To get Heavy Stinger book, you should earn an average of 28.6 tokens per day for 28 days.
Bounty Hunter Event 3/26-4/16, 2015
Verric's Bounty Hunter Post
Bounty Hunter Event 4/01-4/29, 2015
Bounty Hunter Event Prizes
Bounty Hunter Event 3/30-4/20, 2015