From 80 to 86 within 10 days

Player capii has achieved sth amazing;

he has levelled up from 80 to 86 within 10 days(below 10days),and 85 to 86 in just a day.

I wonder what method was used to achieve it.I know many 80+ try their best to do it ; they use rings,items, double xp etc but as far as i know non reached this success of capii.

Please someone enlighten us about this problem.