Complex sentence: When Lady Kale discovered a new enchanted jewel called the Dark Stone, her destiny became clear: using the Dark Stone, and aided by a group of misfit beasts, she has vowed to master the wild magic of Avalon and take control of the kingdom.
Split into simpler sentences: When Lady Kale discovered a new enchanted jewel called the Dark Stone, her destiny became clear. Using the Dark Stone, and aided by a group of misfit beasts, she has vowed to master the wild magic of Avalon and take control of the kingdom.