(You can choose between female or male) Byleth, an android created by you in Fódlan. No one really knew you had advanced technology on your hands. Since they are machine, they still have left to have a heart and emotions. You are working on that heart to make them whole, gathering information from your own experience and others with emotions. In this AU, Jeralt treats them like a son/daughter despite not being related to. The reason why you created them is because you needed a friend.