Frank: Juno's "Secret Weapon"

Warning! May contain Lost Hero and Son of Neptune spoilers! 

"Anyway, Gaea doesn't want you to be one of the seven. Percy Jackson... she believes she can control him. All of the others have weaknesses she can exploit. But you--you worry her. She'd rather kill you right away. That's why she summoned the Laistrygonians. They've been here for days, waiting." -Mars to Frank in The Son of Neptune

***Somewhere in this conversation, Mars called Frank "Juno's secret weapon".***

So... Frank is Juno's secret weapon, huh? Very interesting.
How about we think about the others' weaknesses?

• Percy: He's the loyal one. He puts friends first, regardless of whatever is going on. He's the guy who would sacrifice the world to save a friend. And, as Mars said, Gaea seems to think she can manipulate him.
• Jason: We don't really know Jason that well with his memory being lost and everything. He just seems too powerful. Also, the line "To storm or fire the world must fall" doesn't sound that great...
• Leo: Well, again, the storm or fire line. Also, his fire powers can get out of hand and put everyone in danger, like he did at Aeoleus's (sp?) place. He could also put Frank in danger if he's around Hazel too much. (Hazel has Frank's wooden stick.)
• Piper: Jason. She's a daughter of Aphrodite. Of course her boyfriend is gonna be her weakness. If they break up because of Reyna..... I don't even want to think about that. I like Reyna more, but Piper's the charmspeaker. She's supposed to be the link between the two camps. And you saw how easily she was tempted in the Lost Hero. Jason and Leo went right along with it. They could have been killed. They could have failed. Taking another risk like that wouldn't be good for the quest.
• Hazel: Hazel is just so confused and stressed out. She's finally happy with Frank. Then her past comes back to haunt her, with Leo looking exactly like Sammy and everything. Also, Nico is missing. Her brother. Gone. Bad. And her curse. What if another of the seven accidentally picks up something cursed? Not good.
• [Possibly] Annabeth: We all know that Annabeth's fatal flaw is hubris. (Not hummus. Hubris. AKA pride.) And this "mark of Athena" doesn't sound like it's something that's going to help Annabeth with the whole teamwork element. Her grudge against Hera won't be that helpful, either.

Well, the nice think about Frank is that he's a son of Mars. He knows where his duty lies. AND he can shape-shift. That's pretty amazing.