Another form of the Cold One could be the
Pishtaco a Latin American bogeyman that is a sort of body fat vampire. Clearly, a metaphor for wasting disease but these pale greedy hungry monsters would fit nicely in this setting. The constant greed of the Pishtaco could be about gaining money to buy diamonds. Since the Cold Ones need diamonds. An undead monster obsessed with stealing flesh (to make more shells/bodies) and money (to buy diamonds) fits the narrative.
Any use to you?