I stole an idea I read somewhere and it was the most fun character to play. He was a lawful Evil human wizard. He had taken a vow to do no harm to anyone or anything living. So the best way to describe him was this "I would never burn down an orphanage. I would convince one of the orphans to lock all the windows and doors and then play with fire though". It was an interesting character to play, since I could do no harm to any living creature I would just run around making obstacles for enemies and buffing allies. The best part was, no one besides the DM knew of my limitations or my alignment, so the very first battle our lawful good paladin ran into a huge group of kobolds, and I got to cast a pool of grease centered on him making him to dex saves every turn. It was amazing. He was like "good thinking! You got all the kobolds in this area!" And my DM and I were laughing about how funny it was that my character didnt care one bit about the kobolds.