@valeri112 The only illegal part is to play two accounts on the same world, at the same time. As of now that they changed the rules it is also not allowed for you to
noble from an account you have logged into.
So in short, what is illegal is to play two accounts at the same time on the same world, and to noble an account you have played with an account you are now playing instead.
To co-play on one world, and play yourself on another, is 100% legal.
have fun <3