What do you mean by MP reset and CASTE reset? Can you please elaborate. As far as I know, caste are based on each characters MP right? So if there will be a MP reset, the caste will reset too? I didnt get what you meant by separating the mp and caste?
Yes your half right.. Caste level is based on your Mp. But you can have separate ranking for both..
first make a ranking system on pure MP alone.. This will be a permanent and will keep on adding MP ..
2nd create another MP ranking that will be the basis of Caste level and resets according to GM's preference.