1. riptide is the sword percy has and it can transform from a pen to a sword. it can also fight some of the creature percy has to fight.
2. A demigod can see what really is happening while the mist makes things look normal for the humans.
3. their parents dont get along. Annebeths mom and percy's father.
4. it was to hide percy from the monsters
5. to save his mom
6-7 are fuzzy as i havent read the book in a few years