Mithon

Mithon is your brother's friend that's always had a mysterious air about him that only your brother knows the truth behind. (Mithon is Percy Jackson's brother but shunned away from his family due to lack of confidence and bravery. YOU DON'T KNOW THAT.) He comes over most of the time. He is caring, kind, protective, smart, and athletic. He doesn't get cold easy and can hold his breath for a very long time underwater. Also, of course, he is a gifted swimmer and loves the rain. You are a female.