Birds of a Feather
After Dick Grayson watches his parents fall to their deaths, he moves in with Bruce Wayne.Living with the billionaire didn't seem so bad at first, but Dicks far from happy. Bruce wasn't around for Dick when he needed a parent figure and was forced to grieve alone.So he ran away.
Persephone Jackson saw her mother murdered when she was five.Now she's immortal and eight-teen and has been through two horrific wars, and still, she can't forget that one night. Months after the Gaint War, she felt she needed a break from camp and something led her to Gotham. It might have done with the fact that the city seemed like it was in constant suffering, like her.
Percy Jackson and Batman crossover.
By the way, I adopted this story from @ICantPickAFavFandom.