Chateau Montsombre was a castle in Gallica that the warlord Deparnieux occupied during and for some time prior to the events of The Icebound Land. It was large and threatening, on top of a hill with a road leading up to it, dotted with cages filled with the gruesome remains of Deparnieux's past prisoners.
It had several towers, one of which served as Ranger Halt and Horace's prison while they were held there. It also had a spacious dining room where they ate each evening while Deparnieux attempted to figure out who or what Halt was, as he considered his marksmanship skills and simple, deceiving appearance intriguing and considered the possibility of him being a sorcerer. The dining room was also where Deparnieux ordered the flogging of his assistant and the caging of the cook to lure Halt to try and save them.
Chateau Montsombre was surrounded by a grassy plain, where Halt and Deparnieux dueled in The Icebound Land. Using a heavy-tipped arrow, Halt struck him down and handed command of the castle to Deparnieux's garrison commander, on the conditions that every person who had served in the castle be free to leave; conditions to which he reluctantly accepted.
However, Halt had left a burning torch and oily rags in the keep, setting fire to the castle to make sure Deparnieux's reign of terror was ended once and for all.