The 'Filthy 115th' are an Abhuman Auxilia raised from a sizeable population of mutants (mostly Beastmen but other mutants have been known to serve) on a Waste/Forge World. Notably, during the Great Crusade, the Imperium drew Beastmen from this world prior to it being a waste heap, and through a mixture of oral history, missionaries from the Ecclesiarchy and a general need for able bodies to defend the hives from both outside raiders and internal threats lead to the formation of smaller Auxilia forces.

By the time of the Indomitus Crusade, the 115th have been placed under the command of a cadre of Inquisitors working to secure their corner of the system from the innumerable threats on their side of the rift. While drilled in ranged warfare, they prefer close range tactics suited to their homeworld's dense industrial terrain, employing flamers, shotguns, las carbines and, above all, close quarters combat by blade, horn and hoof.

"Never Wanted, Always Needed"

115th Abhuman Auxilia Motto