While the group wildly starts to flip through pages, Tornak and GG seem to more methodically search through the pages. After about 20 minutes the Goblin and Half-Elf find several symbols that are extremely similar to the one found on the fallen monsters. (5 Pictures, and 6 References)
After bringing the found material to the attention of the group, the focused effort of the team is almost undercut by Tornak's pondering of the cannons, and how much black powder it would take to make such projectiles fly. The excellent focus of the two Arcane inclined members though pulls the research through though. The group figures there are 3 pictures that truly match and 2 references that that actually reference it as well.
The group has the copies of the original sketch plastered all over the table for reference:

- Sketch - House Dimir.jpg (8.15 KiB) Viewed 17338 times
In three separate books they find these matching images:

- Dimir Dagger.jpg (57.3 KiB) Viewed 17338 times

- Dimir Colour.jpg (16.85 KiB) Viewed 17338 times

- Dimir Building.jpg (122.14 KiB) Viewed 17338 times
The dagger looking image is found in a Manual of Guild Weapons and Practices.
The vivid coloured picture is found in the Compendium of Ancient Guilds and Magical Covens.
The image including the symbol is from Architecture Marvels: Underground Cities, and their Cultures.
The text of the Compendium of Ancient Guilds and Magical Covens is mostly ruined. None of the members are able to decipher the ruined text of the book.
The Manual of Guild Weapons and Practices mentions that the House Dimir prefers short slashing weapons that are easily poisoned, and concealed.
In the tome of Architecture Marvels: Underground Cities and their Cultures the group finds that the House Dimir is an Ancient Drow Guild of Assassins. They are considered brutal and deadly even by other Drow sects.
The Dimirs are shrouded in mystery, and many think they have died out, or doubt they even existed in the first place.
While the more martial members of the group start to enjoy an extra beverage, and another helping of dinner, the Arcane focused members persevere and patch together two solid pieces of information.
The last believed mention of the Dimir Guild having been contracted or mentioned was more than 50 years ago, near Katha. The now embroiled City at the heart of the Black Dragon situations.
The second from the Compendium: There was, or possibly is a direct counterpart to this shadowy, Assassins guild; The Selesnya Conclave, a guild that was/is dedicated to preserving what it deems to be the “sacred” lands.
As the group studied they were joined by Lady Onyxarm. Both Heads of the Diplomatic Houses seemed to be impressed with the focus and knowledge displayed by all the members.
"Please rest here in my house for this day. We will provision you in the morning. We will see if we can find any traces of this Guild that opposes this new apparent enemy." Lord Homeforger will offer in a break of the research.
Lady Onyxarm will also chime in:
"Please, if you need any mundane items, our stores are open to you."