Evidence. Fine, here we go!
Rick Riordan's Blog
Q: Is Reyna powerful?
A: Yes.
Q: Is it a god that we have seen in the Percy Jackson/Heroes series?
A: No.
Video
I mean, come on, guys. Reyna sinabi that she looked as if Percy had walked from her worst nightmares. Why does this matter? Read the susunod piece of evidence.
Summary From Very Accurate Library
Demigod Percy Jackson, still with no memory, and his new mga kaibigan from Camp Jupiter, Hazel and Frank, go on a quest to free Death, but their bigger task is to unite the Greek and Roman camps so that the Prophecy of Seven can be fulfilled.
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Do you understand what I mean? I personally believe that Reyna's dad is Thanatos, or whatever his Roman name is. What do you think? Comment.