The elemental trials are meant for two things, to test out your bond with your Soul Beasts and raise your own ranking of that element, and the second is to test your skills and gain new beasts and rewards. There are eight trails, one for every element, and one for every elemental region. They were built close to where the Soul Beasts are kept near the source of mana so they could manifest their forms.

          If you are able to pass through the gauntlet of beasts and mazes you will meet with the Soul Beast at the end and they will gift you with a fragment of their mana to raise your own ability. If you wish to gain a different Soul Beast other than your patron then you will have to fight to prove your worth and that you have an understanding of the basic magic for that element.

          Your power and your beast's abilities go hand in hand. If you're only a rank one fire mage you need to increase your own magic to rank two before you can take the rank two trial. It's how the magic works and there are safeguards in place to make sure you don't try something stupid and burn out your mana channels.