The charcoal burner can be an extremely important building for players approaching maturity in the kingdom of Everwinter Glacier. It's properties of creating charcoal to be traded for soldiers and equipment can be extremely useful in emergencies, and provide a steady supply of troops without spending coins. One can buy over 50 renegades at a time with a full supply of charcoal, which has enormous strategic value if done at the right moment. Other useful items are the 2 unique items for sale, and the wolfhound, which goes twice as fast on the world map as your regular unit. 

Note: The Charcoal burner level 10 is only available to be built with the presence of the Architect camped outside the castle. 

Also, it should be kept in mind that the Native Village must be upgraded to at least level 1 for the Charcoal burner to be built. Also, the Charcoal burner is restricted by experience level. The way I did it was to fully upgrade the Native Village to level 4, then focus on building 4 Charcoal burners. It is advisable to have 6 be the limit, as too many will take up space and produce next to nothing.