After the cutscene in Qufim, head to Norg and speak to Andrause at (I-8).
In order to get the Black Book from him, he will ask that you 'investigate' three randomly chosen mobs in the Sea Serpent Grotto. This is done by using a Soultrapper and Blank Soul Plates.
He will give you a specific list of mobs for you to take pictures of.
To take a picture, equip the Soultrapper in your ranged slot, and the Blank Soul Plates in your ammo slot. You can then use the macro /item "Soultrapper" <t> to take a picture of a mob. You don't have to engage the mob to take a pic.
It is possible to get all 3 done in one game day.
Some monsters can only be found behind doors requiring certain beastcoins for entry:
Once you have traded all 3 he will give you the Black Book (He mentions that if another is required you can return to him.)
Please be aware if you throw your Soultrapper away, Andrause will ask you to wait until the next shipment arrives. (At a guess JP midnight unconfirmed at time of posting.) You can purchase the Soultrapper & Blank Soul Plates from Zandjarl, The Colosseum (F-7).
NOTICE - Soultrapper cannot be used while under the effect of Sneak or Invisible. When attempting to take a shot of a Robber Crab behind the Gold Beastcoin Door, that message appeared.
Game Description
Mission Orders
Seeking to usurp the Tenshodo as the underworld's foremost supplier of contraband, Domina Shantotto requires that you remove its leader, Aldo, from the picture. A clandestine meeting between you and the target
has been arranged in the Gustav Tunnel. All that is needed to initiate contact is a black book, acquirable from Andrause in Norg.
Game Script
SPOILER WARNING: Click here for additional details about this story line.