Dipper Pines

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Dipper Pines is one of the main characters of Return to the Falls. A paranoid, constantly exhausted and slightly neurotic teenager, he's returned to the world of Gravity Falls feeling distinctly more tired and nervous than when he left, thanks to the results of Weirdmageddon.
Not quite as tall as he'd like to be, and finding puberty a distinct disappointment, Dipper has only grown more self-conscious and wary of the world around him since 2012, and eminently more nervous, but all the more close to his sister, Grunkles and the town of Gravity Falls - to such an extent that he was extremely excited to return. 
Now in a relationship with Pacifica Northwest, Dipper is ultimately happier than he's ever been - despite Summer 2013 seemingly throwing everything it can at him. 
=== Return to the Falls ===
Dipper's first instincts are to be sceptical of Pacifica, though he's well aware of her partial reform since the events of Face It and Northwest Mansion Mystery. However, with his own admittance that she's a 'pretty face' on the table and his writings about her in Journal 3, it's pretty obvious he had feelings regarding her from the day he left the town.
Mabel reveals that he had been reading Pacifica's blog in the meantime, and had considered trying to contact her in the interim - sadly, his nerves won out, but Mabel kept Pacifica updated with him.
Dipper's self esteem and anxiety is by far his greatest enemy. Throughout Return to the Falls he's been second guessing himself, his relationship with Pacifica and his ability to keep her. He has, however, started showing bursts of flirtation, confidence and his knack for sarcasm when least expected, not to mention his finest trait from last summer - immense bravery, a natural protective instinct and an incredible knack for investigation and piecing things together.
While his greatest fear still appears to be the possibility of losing her, Dipper is steadily growing to understand that she really does love him, and only him - with very little interest in his extenuating circumstances or downsides. 
All the same, old habits die hard. He's still got an endless crush on Wendy, a desperate wish to improve himself and is starting to develop his Grunkle Ford's wishes for glory and success.