Daniel Arthur Cahill.
Dan Cahill that is his real name.
Dan Cahill's full name is Daniel Arthur Cahill.
Amy and Dan are siblings. Amy loves Dan as a sibling and a brother.
i think his real life name is Patrick.
In Book Seven: The Viper's Nest: Amy and Dan Cahill figure out they are Madrigals
Hope Cahill and Arthur Trent
The older sister of Dan Cahill.
Madrigal
It is Arthur
Yes, as indicated by their last names, they are related, and this relation is that of being siblings.
Ashley Jackson will play Amy Cahill. Adam Hicks will play Dan Cahill.