Manga where children play with a device that uses crystals which contain "Monsters."?
As I remember some people most likely scientists I believe, created some sort of device that uses crystallized monsters that kids can play with as a game and these kids battle each other with their own monsters. I remember that it's about the size of their hands and they need to attach the crystals to a device to play and there are a lot of different monsters and also I remember the main character being really strong and his monster is a dragon and he always said something like if your care for your monster then they'll care for you and stuff. The main character lives in a trailer with his grandma and that's all I can remember.
As I remember some people most likely scientists I believe, created some sort of device that uses crystallized monsters that kids can play with as a game and these kids battle each other with their own monsters. I remember that it's about the size of their hands and they need to attach the crystals to a device to play and there are a lot of different monsters and also I remember the main character being really strong and his monster is a dragon and he always said something like if your care for your monster then they'll care for you and stuff. The main character lives in a trailer with his grandma and that's all I can remember.