I was reading through good old TV Tropes and I found this one which made me think of Fray from the DRK questline: http://tvtropes.org/pmwiki/pmwiki.ph...henLetMeBeEvil
Going by the BLM storyline though, I think a THM/BLM would fit this type of character very well too. They have a tainted past and an individualistic approach to their religion, they seem to always be at odds with Conjurers and WHMs, and Gridanians aren't known for being accepting of outsiders. I haven't seen the full BLM storyline in Heavensward yet, but I wouldn't be surprised if the "Defiant" BLMs had this as one of their motives.
My Main character I use for RPing, Miranda, is a SMN. She almost fell into this trope herself due to all the disrespect she recieved from the townsfolk in her time as an adventurer (particularly Gridanians) and the only reason she didn't was because the Scions recognized her potential (thus giving her a neutral haven) and she was lucky enough to find an Allagan Soul Gem.
Note how they put "forces of good" and "evil" in quotes on the trope page too...I could definitely see a DRK or BLM going down this path just from being distrusted and ostracized for their dark & misundertood natures.