Shadow Mercenaries

So today, this Shadow Mercenary camp showed up right outside my castle, which is at the bottom corner of your castle. When I clicked on the camp, the page that I am showing above popped up. It allows me to buy soldiers using rubies instead of coins and food, which is what it usually takes. Surprisingly, after I compared the stats of the soldiers and tools that the Shadow Mercenary camp was selling to the ones that you can produce, they have the exact same stats, except for the fact that the soldiers that this camp sells requires no food, which is quite helpful. Unfortunately,  You can only buy a limited amount of these soldiers or tools depending on your level. All of the things that this camp sells is actually quite cheap, especially for players to purchase rubies.