Well, a likely trait would be a sense of superiority. As the God of Pride, Percy in fanfic might look down on others. He may not tolerate any form of disrespect towards himself and might react harshly. Also, he could be very possessive about his powers and status. He would want everyone to recognize his greatness and might go to great lengths to prove it. In some fanfictions, this could lead to conflicts with other characters who don't accept his new role so easily.
In fanfiction, if Percy is the God of Pride, he may have a haughty demeanor. He would carry himself in a way that shows he thinks he is above others. His actions would be more self - centered, focused on enhancing his own glory. For instance, he might take on challenges not for the greater good but just to show off his power. His speech could also be filled with boastful statements, constantly reminding others of his status as the God of Pride. Additionally, his relationships with other characters would be affected. Friends might become distant as they struggle to deal with his newfound pride - filled personality.