You should be able to get this trophy by the time you reach shop level 12 (completing Big Jade Quest number 3) on any of your characters except Baldren. Once you've completed this side quest, go to a scrolls vendor and buy the newly available Enchanted resistance scroll for 150,000 rainbow coins (by far the most expensive skill so far). Use it on the character that you want to use to get this trophy and voila. Of course make sure that the said character has already learnt every other active and passive skills available to them.