Hmm, I'm a bit on the edge about it, since that last sentence then becomes a run-on sentence, making it more difficult to read. We can still keep the part about being separated from his family though:
Alfredo Ventura is a young boy who always wanted to be a Dreamer, the powerful heroes of his favorite storybook. But when he must separate from his family, he discovers the power that already resides in him, which can bring peace to the World of Gaia once and for all.
Actually wait, as I'm writing this I got an idea to end this blurb in a question:
Alfredo Ventura is a young boy who always wanted to be a Dreamer, the powerful heroes of his favorite storybook. But when he must separate from his family, he discovers the power that already resides in him. Is it enough to bring peace to the World of Gaia once and for all?
I'm sorry for not thinking of this earlier, but sometimes question endings can help with getting the reader interested, since it isn't entirely specified how the story will end and now they have to read it to find out . But I'll leave it to you to pick which one you prefer.