default gamemode in project settings is a C++ Gamemode that defines the defaults spawn player:
// set default pawn class to our Blueprinted character
static ConstructorHelpers::FClassFinder<APawn> PlayerPawnBPClass(TEXT("/Game/ThirdPerson/Blueprints/BP_ThirdPersonCharacter"));
if (PlayerPawnBPClass.Class != NULL)
{
DefaultPawnClass = PlayerPawnBPClass.Class;
}