OK firstly let me say, this isn't exactly a profitable exploit and I'm not sure if there is just tonnes of NPC's that let you do this, anyway here's what I found:
This NPC in the starting Asura location asks you about feeding people or something, giving you options for Charisma, Ferocity and Dignity - after you choose one though, you can just spam it over and over until you max out whichever personality you want.
Now I'm maxxed out Ferocity at lvl 6 yey!