Risen

You have to do this on your Magician playthrough and finish the training with all the magicians in the volcano keep. When you finished the training you have to level up all of the 3 different crystal magic spells with your EXP/LP and some gold. Before you max out one crystal magic spell technique make save, level it up to the max,reload your save and repeat this method on the other 2 crystal magic techniques. Once you did it on the third the cheevo will pop!

The trainers for each crystal magic style are: IGNATIUS(FIREBALL),VITUS(MAGICSHOT) and PALLAS(FROST)

If you dont have enough XP there is a glitch in the swamp near the banditcamp with a guy called Rhobart who lives in a shed at the swamp. You can sell him the weed you collected so far for 50 EXP and 70GOLD and sell it all to him in 10piece stacks. When you sold all of your weed knock him out with a weapon,loot your weed back, wait till he wakes up and sell it to him again. You can repeat this process as often as you want.

What i did to speed up the process of this exploit was using a good weapon, switch the game to easy difficulty and have as much weed in my inventory as possible(i also bought it from other traders as well) so i can sell more stacks each time before I knock him out.