Spirit Masters have been the most essential profession within the last several tens of thousands of years. Spirit Masters were not only rare, but the majority of them were also weak. But with the advent of Spirit devices, this paradigm had shifted. Low rank Spirit Masters could now become much more powerful by relying on their Spirit Power and Spirit devices. Afterward, Spirit mechas began to appear, allowing Spirit Masters to become even stronger.
Spirit Mechas are operated by using soul power from Spirit Power batteries, thus allowing it's user to display strength far surpassing their own. The first Spirit Mechas were developed in a larger form, the factor being that the larger they were, the larger the Spirit Power battery they could install as well as the number of weapons it could be equipped with.
As technology progressed, Mechas became operable by ordinary people with sufficiently strong bodies. From then on, Spirit Mechas became the main weapon of the modern army.
In the history of Mecha development, there have been periods where the form was small, medium, and large. This is the basic outline of Mecha development. This was a process of trial and error and it's resulting improvements. It involved the perfection of Spirit circuits, various innovations, and the advancement of technology by leaps and bounds. Mechas have only grown increasingly more important in wars ever since their creation.
With the aid of Spirit devices, an ordinary person might be able to match up to a Spirit Grandmaster, and with a Mecha, they could even possibly contend with a five ring Spirit King. Mechas truly do offer tremendous power to it's user, but even so, it cannot give an ordinary person the fighting power of an eight ring Spirit Douluo or a nine ring Title Douluo. At the very least, it is impossible at this point in time.
The Mechas one can commonly see range from five to eight meters in height and have some peculiar differences depending on what type of Mecha they are. These are the modern medium-sized Mechas. From their research, Soul Guide Masters came to the conclusion that a combination of bulk and flexibility along with a balance of offensive and defensive capabilities were the most suitable for the army. But these are just the standardized mechas for ordinary people. White and yellow mechas are of the same category.