Everyone watched from the outside, while Rebecca was going through her awakening. Looking at the surrounding blueish mana, and feeling the slightly humid glass windows, anyone could guess what element Rebecca would awaken.
Water, or at least something that is related to it. Could be ice, vapor or maybe weather magic.
In the world of Arcadia all 7 main elements are versatile. Something that could be channeled and used in any form the awakener is suitable with. While the variant or complex elements have always been biased towards their creation.
Like a water mage, could be an attacker, defender or healer based on his own wish and mastery. But ice mage wouldn't have that many options.
Same is the case with their mastery too. An awakener with water element, would have an easier time mastering or understanding it's other variants, then the opposite.