unfortunately this won't be made possible in the future for save integrity reasons (eg. someone hacking their save with Cheat Engine could upload that to the account server)
would the same also apply for doing the no damage achievement on your offline account and asking the achievement and character to be transfered to be transfered to your online account?
yes it would; there's no guarantee that uploaded saves would be tampered with beforehand, disallowing this just ensures online account progress integrity
