you and haku met when you accidentally stumbled spin the odd place and your oblivious parents forced you to go into. After your crazy adventure, like haku promised, he did see you again. You visit him there because you made a deal with Yubaba that you both can come and go as you please if you work at the bath house sometimes your there and he visits you outside if he continues to be his apprentice most of the time too, the system you both had was amazing and you got to see him often