In theory: If anyone ask me to recommend Nain027 if he add me on his CV for reference then I don't think I am going to tell them anything negative as he worked very well in my business. I have no complain for the job he does for my service.
Oof. This guy obviously has no problem lying to anybody at any given time -- I'd think that should weigh on your decision to act as a reference for him. What would happen in the case that you vouched for him and then he went on to screw over a future employer?
Funny how this turned out to be somewhat prophetic:
I will create 100 more accounts as soon as I can.
I am certain he has more accounts currently at work but he'll be a bit more clever in masking them from hereon out.