If you’re using all the tricks in the book and have fully upgraded the buildings, heroes, familiars, and the research tree, the shelter can have a significant capacity. With all things considered, the shelter can always take 310 000 troops to be protected from enemy attacks. You can temporarily increase that number to a whopping 465 000 by using a 50% Army Size Boost. However, keeping that boost up will drain you of available Gems rapidly.