Annabeth Chase
The writer of the books, Rick Riordan, was asked in an interview, "Do you feel those who said the main characters, such as Grover and Annabeth, are heroes in their own right?". He answered, "Annabeth is Percy's rational side. She can think through things and look at options that sometimes evade Percy in his moments of battle panic." This means she can think even when there is a fight going on, unlike Percy, and can find solutions to problems. That is also why Annabeth is a daughter of Athena because she is the goddess of wisdom and battle strategy.