So this is where we are thus far.
Kahir, Varg, and Lazarus, witnessed the overly guarded transportation of some oddly mystical/magical/divine object. With a little gumption and a lot of luck, they managed to locate where it was stored, barely escaping notice.
Bronlodious was assigned to research and protect the Keep by the River with some basic wards, which he did well, creating an ingenious alarm of illusions to distract would-be assaulters.
Kahir, Varg, and Lazarus were assigned by Conrad to intercept and escort a caravan from Diobel to the Keep by the River. No reason was given for the need for security, and no reason was given why the three of them should attend to it instead of the Keep’s force of men-at-arms and rangers.
The three erstwhile travelers discovered the caravan aflame, besieged by two humanoid constructs of flame. Through some quick thinking and brute strength, they overcame the elemental fires in time to defeat the undead who were raised from the corpses of the previous caravaners. Concurrently, Xing Wei, having left his pride to further his knowledge, smelled the fires and heard the sounds of battle and decided to investigate. Upon nearing the melee, Xing discovered a practitioner of magic hidden from the Erstwhile Three. They battled, Xing managed to force the Mage to run, and despite his efforts could not successfully track it.
During the battle with the undead, Kahir discovered the contents of one of the camel-drawn wagons: an obsidian box laid atop a bed of pure white sand. His first instinct: use the box to beat the skeleton, which was unsuccessful. However, the contents of the box were discovered to be that of the left leg of some reverse-articulated being of great stature. Lazarus speculated a demon, or other being of the lower planes, but only after stirring the blackened sand beneath the limb, sacrificing the life of his left hand in the process.
The Erstwhile Three, now Four, returned to the Keep by the River with the box, and in the process almost killing the camels carrying their shadowy cargo. Upon returning to the Keep, the Erstwhile Four met Bronlodious, who was in the midst of setting his wards – and who may be going crazy from hearing voices – and became the Erstwhile Five. They hid the box in a deviously simple location (under the stairs, because nobody looks there), and abandoned the castle. To Absalom they travel, in the hopes that their patron, Conrad, will know best how to handle whatever limb resides in the rune-covered obsidian crate.