My father is the brother of your sister. What relative am I of yours? Cousin, nephew, son, uncle, son-in-law?

catdog.

you're my brother's child, so nephew or niece. Or you're me, in which case you're my son/daughter. You don't provide enough information to choose more tightly.

Son or nephew depending on how many brothers the sister's got.

It don't matter none, son. This is Tennessee.

You are the pedo uncle ewwww

Family headspins!

Cousin

Nephew

then your father is my brother and you are my nephew

Nephew

You're my daughter. come here, daughter.