Disgaea: Gehenna's Holy Queen by The Ansem Man
http://www.fanfiction.net/s/4940130/1/Disg...nnas_Holy_Queen
Who says you need things like "experience" or "sanity" to be a badass frickin' overlord? Well, if you're the main character, that's going to be the least of your worries if you're strong enough to end the world. So learneth Konoka Konoe.
Crossover - Disgaea & Negima
Konoka is an Overlord. Only read first chapter so far, but it looks promising!!!! Semi serious though.