This usually is the product of a specific training, lifestyle and physiology, featuring differences even among the members of the same species, and thus it heavily depends on the conformation of a single individual. On top of that, it is often related to willpower and determination, making it even more unique. For this reason it is recommended to not scale stamina between characters that are comparable or superior to each other in terms of statistics such as Attack Potency, Durability etc. It should be allowed only when levels of stamina are explicitly defined as common and natural traits shared by members of the same species or group, or through direct statements and evidences of characters being comparable in such aspect.