The Lootmark slows down the rate at which Raids appear and prohibits the deployment of anything within its range (and cannot be placed if any tile within its range is occupied). This is because as the player defeats the various bosses throughout the campaign, the Lootmark's surroundings will be occupied by trophies corresponding to the boss as follows (clockwise from the top left):
Units and Constructs cannot be deployed/built within the Lootmark's range; the Lootmark cannot be built on locations where units and other Constructs would overlap with its range.
Skill
Recollect
Passive
Effect
Filled with tokens of formidable foes; some are commemorations, while others are premonitions.